Immunization , or immunisation , is the process by which an individual's immune system becomes fortified against an infectious agent (known as the immunogen ).
107-426: When this system is exposed to molecules that are foreign to the body, called non-self , it will orchestrate an immune response, and it will also develop the ability to quickly respond to a subsequent encounter because of immunological memory . This is a function of the adaptive immune system . Therefore, by exposing a human, or an animal, to an immunogen in a controlled way, its body can learn to protect itself: this
214-622: A chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H 2 O). In the kinetic theory of gases , the term molecule is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions , such as hydrogen bonds or ionic bonds , are typically not considered single molecules. Concepts similar to molecules have been discussed since ancient times, but modern investigation into
321-440: A plane , e.g. graphene ; or three-dimensionally e.g. diamond , quartz , sodium chloride . The theme of repeated unit-cellular-structure also holds for most metals which are condensed phases with metallic bonding . Thus solid metals are not made of molecules. In glasses , which are solids that exist in a vitreous disordered state, the atoms are held together by chemical bonds with no presence of any definable molecule, nor any of
428-663: A smallpox vaccine , making her the first person to take a vaccine in India. The widespread rumour since the nineteenth century that vaccination was documented in India before the discoveries of Edward Jenner can all be traced to propaganda tracts written in Sanskrit and the Indian vernaculars by colonial officers, in the hope of convincing pious Indians to accept the newly discovered Jennerian procedure and abandon older variolation practices. A landmark anthropological study by Ralph Nicholas described
535-866: A 0.5–2.0% mortality rate, but that was considerably less than the 20–30% mortality rate of the disease itself. Two reports on the Chinese practice of inoculation were received by the Royal Society in London in 1700; one by Dr. Martin Lister who received a report by an employee of the East India Company stationed in China and another by Clopton Havers . According to Voltaire (1742), the Turks derived their use of inoculation from neighbouring Circassia . Voltaire does not speculate on where
642-429: A bud from one plant into another. It derives from Latin in- 'in' + oculus 'eye' (and by metaphor , 'bud'). (The term innocuous is unrelated, as it derives from Latin in- 'not' + nocuus 'harmful'.) Inoculation originated as a method for the prevention of smallpox by deliberate introduction of material from smallpox pustules from one person into the skin of another. The usual route of transmission of smallpox
749-565: A certain number of these atoms united by attraction to form a single molecule . In coordination with these concepts, in 1833 the French chemist Marc Antoine Auguste Gaudin presented a clear account of Avogadro's hypothesis, regarding atomic weights, by making use of "volume diagrams", which clearly show both semi-correct molecular geometries, such as a linear water molecule, and correct molecular formulas, such as H 2 O: In 1917, an unknown American undergraduate chemical engineer named Linus Pauling
856-399: A dimension of a few angstroms (Å) to several dozen Å, or around one billionth of a meter. Single molecules cannot usually be observed by light (as noted above), but small molecules and even the outlines of individual atoms may be traced in some circumstances by use of an atomic force microscope . Some of the largest molecules are macromolecules or supermolecules . The smallest molecule
963-459: A disease. Vaccines against microorganisms that cause diseases can prepare the body's immune system, thus helping to fight or prevent an infection . The fact that mutations can cause cancer cells to produce proteins or other molecules that are known to the body forms the theoretical basis for therapeutic cancer vaccines . Other molecules can be used for immunization as well, for example in experimental vaccines against nicotine ( NicVAX ) or
1070-435: A graphical type of formula called a structural formula may be needed. Structural formulas may in turn be represented with a one-dimensional chemical name, but such chemical nomenclature requires many words and terms which are not part of chemical formulas. Molecules have fixed equilibrium geometries—bond lengths and angles— about which they continuously oscillate through vibrational and rotational motions. A pure substance
1177-404: A greatly reduced risk of death – 1–2% – compared to those contracting Variola major with 30% mortality. Infection via inhaled viral particles in droplets spread the infection more widely than the deliberate infection through a small skin wound. The smaller, localised infection is adequate to stimulate the immune system to produce specific immunity to the virus, while requiring more generations of
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#17328454746201284-450: A level of immunization that makes the spread and survival of the disease impossible. Despite the severity of certain illnesses, the cost of immunization versus the social marginal benefit means that total eradication is not always the end goal of immunization. Though it is hard to tell exactly where the socially optimal outcome is, we know that it is not the eradication of all disease for which an immunization exists. In order to internalize
1391-401: A molecule is inherently an operational definition. Philosophically, therefore, a molecule is not a fundamental entity (in contrast, for instance, to an elementary particle ); rather, the concept of a molecule is the chemist's way of making a useful statement about the strengths of atomic-scale interactions in the world that we observe. Inoculation Inoculation is the act of implanting
1498-471: A pathogen or other microbe or virus into a person or other organism. It is a method of artificially inducing immunity against various infectious diseases . The term "inoculation" is also used more generally to refer to intentionally depositing microbes into any growth medium , as into a Petri dish used to culture the microbe, or into food ingredients for making cultured foods such as yoghurt and fermented beverages such as beer and wine. This article
1605-515: A person or other recipient; vaccination is the act of implanting or giving someone a vaccine specifically; and immunization is the development of disease resistance that results from the immune system 's response to a vaccine or natural infection. Until the early 1800s inoculation referred only to variolation (from the Latin word variola = smallpox), the predecessor to the smallpox vaccine . The smallpox vaccine, introduced by Edward Jenner in 1796,
1712-951: A quantity determined by private marginal benefits. By running immunization programs organizations are able to move privately under-immunized communities towards the social optimum. In the United States, race and ethnicity are strong determinants of utilization of preventive and therapeutic health services as well as health outcomes. Rates of infant mortality and most of the leading causes of overall mortality have been higher in African Americans than in European Americans. A recent analysis of mortality from influenza and pneumonia revealed that African Americans died of these causes at higher rates than European Americans in 1999–2018. Contributing to these racial disparities are lower rates of immunization against influenza and pneumococcal pneumonia. During
1819-401: A regular arrangement of molecules (as in a crystal). Microwave spectroscopy commonly measures changes in the rotation of molecules, and can be used to identify molecules in outer space. Infrared spectroscopy measures the vibration of molecules, including stretching, bending or twisting motions. It is commonly used to identify the kinds of bonds or functional groups in molecules. Changes in
1926-457: A small cross with a razor in the arm" of his subject and puts "a little of the matter" into the cut which was afterwards bound up with a bandage. Subsequent visitors who described this practice included the British traveller William Cornwallis Harris and Dr. Petit of the French scientific mission of 1839–1841. Inoculation against smallpox seems to have been known to West Africans, more specifically
2033-605: A theory has not yet been discovered in any Sanskrit or vernacular treatise. Doctors who performed variolation were known as Tikadars . By the 18th century, variolation was widely practiced in India. Several historians have suggested that variolation may be older than the 18th century in India. Oliver Coult in 1731 wrote that it had been "first performed by Dununtary a physician of Champanagar". However these reports have been called into question. Vaccinations were introduced to India in 1802, when 3-year-old girl in Mumbai received
2140-429: A widening marginal benefit reaching a social optimum becomes more difficult for governments to achieve through subsidies. Outside of government intervention through subsidies, non profit organizations can also move a society towards the socially optimal outcome by providing free immunizations to developing regions. Without the ability to afford the immunizations to begin with, developing societies will not be able to reach
2247-402: Is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are termed shared pairs or bonding pairs , and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is termed covalent bonding . Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, and
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#17328454746202354-406: Is a good example of a disease whose social optimum leaves enough room for outbreaks in the United States that often lead to the deaths of a handful of individuals. There are also examples of illnesses so dangerous that the social optimum ended with the eradication of the virus, such as smallpox . In these cases, the social marginal benefit is so large that society is willing to pay the cost to reach
2461-455: Is a very simple type of chemical formula. It is the simplest integer ratio of the chemical elements that constitute it. For example, water is always composed of a 2:1 ratio of hydrogen to oxygen atoms, and ethanol (ethyl alcohol) is always composed of carbon, hydrogen, and oxygen in a 2:6:1 ratio. However, this does not determine the kind of molecule uniquely – dimethyl ether has the same ratios as ethanol, for instance. Molecules with
2568-405: Is an active form of immunization. Active immunization can occur naturally when a person comes in contact with, for example, a microbe. The immune system will eventually create antibodies and other defenses against the microbe. The next time, the immune response against this microbe can be very efficient; this is the case in many of the childhood infections that a person only contracts once, but then
2675-427: Is called active immunization. The most important elements of the immune system that are improved by immunization are the T cells , B cells , and the antibodies B cells produce. Memory B cells and memory T cells are responsible for a swift response to a second encounter with a foreign molecule. Passive immunization is direct introduction of these elements into the body, instead of production of these elements by
2782-457: Is caused by individuals making decisions based on their private marginal benefit instead of the social marginal benefit. Society's undervaluing of immunizations means that through normal market transactions we end up at a quantity that is lower than what is socially optimal. For example, if individual A values their own immunity to an antigen at $ 100 but the immunization costs $ 150, individual A will decide against receiving immunization. However, if
2889-435: Is composed of molecules with the same average geometrical structure. The chemical formula and the structure of a molecule are the two important factors that determine its properties, particularly its reactivity . Isomers share a chemical formula but normally have very different properties because of their different structures. Stereoisomers , a particular type of isomer, may have very similar physico-chemical properties and at
2996-431: Is derived from French molécule (1678), from Neo-Latin molecula , diminutive of Latin moles "mass, barrier". The word, which until the late 18th century was used only in Latin form, became popular after being used in works of philosophy by Descartes . The definition of the molecule has evolved as knowledge of the structure of molecules has increased. Earlier definitions were less precise, defining molecules as
3103-452: Is documented in India from the eighteenth century, thanks to the 1767 account by the Irish-born surgeon John Zephaniah Holwell . Holwell's extensive 1767 description included the following, that points to the connection between disease and "multitudes of imperceptible animalculae floating in the atmosphere": They lay it down as a principle, that the immediate cause of the smallpox exists in
3210-480: Is essential for the understanding of the chemical bond. The simplest of molecules is the hydrogen molecule-ion , H 2 , and the simplest of all the chemical bonds is the one-electron bond . H 2 is composed of two positively charged protons and one negatively charged electron , which means that the Schrödinger equation for the system can be solved more easily due to the lack of electron–electron repulsion. With
3317-545: Is immune. Artificial active immunization is where the microbe, or parts of it, are injected into the person before they are able to take it in naturally. If whole microbes are used , they are pre-treated. The importance of immunization is so great that the American Centers for Disease Control and Prevention has named it one of the "Ten Great Public Health Achievements in the 20th Century". Live attenuated vaccines have decreased pathogenicity. Their effectiveness depends on
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3424-412: Is known as a positive consumer externality on society. In addition to providing the individual with protection against certain antigens it adds greater protection to all other individuals in society through herd immunity . Because this extra protection is not accounted for in the market transactions for immunizations we see an undervaluing of the marginal benefit of each immunization. This market failure
3531-467: Is mentioned in the Ayurvedic text Sact'eya Grantham . The outside world was exposed to it later on, as evidenced by the French scholar Henri Marie Husson, who noted it in the journal Dictionaire des sciences médicales . However, the idea that inoculation originated in India has been also taken in account, as few of the ancient Sanskrit medical texts described the process of inoculation. Variolation
3638-473: Is now also known as variolation . Inoculation has ancient origins, and the technique was known in India, Africa, and China. The earliest hints of the practice of inoculation for smallpox in China come during the 10th century. A Song dynasty (960–1279) chancellor of China , Wang Dan (957–1017), lost his eldest son to smallpox and sought a means to spare the rest of his family from the disease, so he summoned physicians, wise men, and magicians from all across
3745-404: Is primarily about the use of inoculation for producing immunity against infection . Inoculation has been used to eradicate smallpox and to markedly reduce other infectious diseases such as polio . Although the terms "inoculation", " vaccination ", and "immunization" are often used interchangeably, there are important differences. Inoculation is the act of implanting a pathogen or microbe into
3852-556: Is the diatomic hydrogen (H 2 ), with a bond length of 0.74 Å. Effective molecular radius is the size a molecule displays in solution. The table of permselectivity for different substances contains examples. The chemical formula for a molecule uses one line of chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, and plus (+) and minus (−) signs. These are limited to one typographic line of symbols, which may include subscripts and superscripts. A compound's empirical formula
3959-617: Is the primary interaction occurring in ionic compounds . The ions are atoms that have lost one or more electrons (termed cations ) and atoms that have gained one or more electrons (termed anions ). This transfer of electrons is termed electrovalence in contrast to covalence . In the simplest case, the cation is a metal atom and the anion is a nonmetal atom, but these ions can be of a more complicated nature, e.g. molecular ions like NH 4 or SO 4 . At normal temperatures and pressures, ionic bonding mostly creates solids (or occasionally liquids) without separate identifiable molecules, but
4066-529: The Avogadro constant using three different methods, all involving liquid phase systems. First, he used a gamboge soap-like emulsion, second by doing experimental work on Brownian motion , and third by confirming Einstein's theory of particle rotation in the liquid phase. In 1927, the physicists Fritz London and Walter Heitler applied the new quantum mechanics to the deal with the saturable, nondynamic forces of attraction and repulsion, i.e., exchange forces, of
4173-963: The Ga-Adangbe people of Accra . An enslaved African named Onesimus in the Province of Massachusetts Bay explained the inoculation procedure to Cotton Mather during the 18th century; he reported to have acquired the knowledge from Africa. Most Old World diseases of known origin can be traced to Africa and Asia and were introduced to Europe over time. Smallpox originated in Africa or Asia, plague in Asia, cholera in Asia, influenza in Asia, malaria in Africa and Asia, measles from Asian rinderpest , tuberculosis in Asia, yellow fever in Africa, leprosy in Asia, typhoid in Africa, syphilis in America and Africa, herpes in Africa, zika in Africa. Thus
4280-563: The King 's physician. Sufficient interest arose that Maitland gained permission to test inoculation at Newgate Prison on six prisoners due to be hanged in exchange for their freedom, an experiment which was witnessed by a number of notable doctors. All survived, and in 1722 the Prince of Wales' daughters received inoculations. The practice of inoculation slowly spread amongst the royal families of Europe, usually followed by more general adoption amongst
4387-466: The 1880s vaccine/vaccination referred only to smallpox, but Louis Pasteur developed immunization methods for chicken cholera and anthrax in animals and for human rabies, and suggested that the terms vaccine/vaccination should be extended to cover the new procedures. This can cause confusion if care is not taken to specify which vaccine is used e.g. measles vaccine or influenza vaccine. Immunization can be achieved in an active or passive manner: vaccination
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4494-459: The 18th century (according to Voltaire, there was a 60% incidence of first infection, a 20% mortality rate, and a 20% incidence of severe scarring), many parents felt that the benefits of inoculation outweighed the risks and so inoculated their children. Two forms of the disease of smallpox were recognised, now known to be due to two strains of the Variola virus . Those contracting Variola minor had
4601-602: The British ambassador to the Ottoman Empire from 1716 to 1718. She witnessed firsthand the Ottoman use of inoculation in Istanbul , and was greatly impressed: she had lost a brother to smallpox and bore facial scars from the disease herself. When a smallpox epidemic threatened England in 1721, she called on her physician, Charles Maitland , to inoculate her daughter. She invited friends to see her daughter, including Sir Hans Sloane ,
4708-473: The COVID-19 pandemic, death rates have been higher in African Americans than European Americans and vaccination rates have lagged in African Americans during the roll-out. Among Hispanics immunization rates are lower than those in non-Hispanic whites. Molecule A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds ; depending on context,
4815-469: The Chemical Bond" in which he used quantum mechanics to calculate properties and structures of molecules, such as angles between bonds and rotation about bonds. On these concepts, Pauling developed hybridization theory to account for bonds in molecules such as CH 4 , in which four sp³ hybridised orbitals are overlapped by hydrogen 's 1s orbital, yielding four sigma (σ) bonds . The four bonds are of
4922-623: The Circassians derived their technique from, though he reports that the Chinese have practiced it "these hundred years". It was introduced into England from Turkey by Lady Mary Wortley Montagu in 1721 and used by Zabdiel Boylston in Boston the same year. In 1798 Edward Jenner introduced inoculation with cowpox ( smallpox vaccine ), a much safer procedure. This procedure, referred to as vaccination , gradually replaced smallpox inoculation, now called variolation to distinguish it from vaccination. Until
5029-423: The added benefit of herd immunity means person B values person A's immunity at $ 70 then the total social marginal benefit of their immunization is $ 170. Individual A's private marginal benefit being lower than the social marginal benefit leads to an under-consumption of immunizations. Having private marginal benefits lower than social marginal benefits will always lead to an under-consumption of any good. The size of
5136-456: The arm it is laid in as yeast in a piece of dough; it ferments, and diffuses through the whole mass of blood the qualities with which it is impregnated. The pustules of the child in whom the artificial small-pox has been thus inoculated are employed to communicate the same distemper to others. There is an almost perpetual circulation of it in Circassia; and when unhappily the small-pox has quite left
5243-441: The arrangements of electrons yield absorption or emission lines in ultraviolet, visible or near infrared light, and result in colour. Nuclear resonance spectroscopy measures the environment of particular nuclei in the molecule, and can be used to characterise the numbers of atoms in different positions in a molecule. The study of molecules by molecular physics and theoretical chemistry is largely based on quantum mechanics and
5350-460: The body does not need to produce these elements itself. Currently, antibodies can be used for passive immunization. This method of immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and if there are no B cells to produce more antibodies, they will disappear. Passive immunization occurs physiologically, when antibodies are transferred from mother to fetus during pregnancy , to protect
5457-463: The body itself. Immunization happens in various ways, both in the wild and as done by human efforts in health care . Natural immunity is gained by those organisms whose immune systems succeed in fighting off a previous infection, if the relevant pathogen is one for which immunization is even possible. Natural immunity can have degrees of effectiveness (partial rather than absolute) and may fade over time (within months, years, or decades, depending on
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#17328454746205564-539: The country, the inhabitants of it are in as great trouble and perplexity as other nations when their harvest has fallen short... Voltaire does not speculate on where the Circassians derived their technique from, though he reports that the Chinese have practiced it "these hundred years". The Turkish practice was presented to the Royal Society in 1714 and 1716, when the physicians Emmanuel Timoni and Giacomo Pylarini independently sent letters from Istanbul. Inoculation
5671-484: The development of fast digital computers, approximate solutions for more complicated molecules became possible and are one of the main aspects of computational chemistry . When trying to define rigorously whether an arrangement of atoms is sufficiently stable to be considered a molecule, IUPAC suggests that it "must correspond to a depression on the potential energy surface that is deep enough to confine at least one vibrational state". This definition does not depend on
5778-552: The disorder infect the Army in the natural way and rage with its usual virulence, we have more to dread from it than from the sword of the enemy." This was the first mass inoculation of an army, and was successful, with only isolated infections occurring, and no regiments incapacitated by the disease. Inoculation grew in popularity in Europe through the 18th century. Given the high prevalence and often severe consequences of smallpox in Europe in
5885-421: The disparity is determined by the value that society places on each different immunization. Many times, immunizations do not reach a socially optimum quantity high enough to eradicate the antigen. Instead, they reach a social quantity that allows for an optimal amount of sick individuals. Most of the commonly immunized diseases in the United States still see a small presence with occasional larger outbreaks. Measles
5992-649: The empire to convene at the capital in Kaifeng and share ideas on how to cure patients of it until an allegedly divine man from Mount Emei carried out inoculation. However, the sinologist Joseph Needham states that this information comes from the Zhongdou xinfa (種痘心法) written in 1808 by Zhu Yiliang, centuries after the alleged events. The first clear and credible reference to smallpox inoculation in China comes from Wan Quan 's (1499–1582) Douzhen Xinfa (痘疹心法) of 1549, which states that some women unexpectedly menstruate during
6099-551: The fetus before and shortly after birth. Artificial passive immunization is normally administered by injection and is used if there has been a recent outbreak of a particular disease or as an emergency treatment for toxicity, as in for tetanus . The antibodies can be produced in animals, called "serum therapy," although there is a high chance of anaphylactic shock because of immunity against animal serum itself. Thus, humanized antibodies produced in vitro by cell culture are used instead if available. Immunizations impose what
6206-464: The heavenly bodies. The viewpoint of Leucippus and Empedocles, along with the aether, was accepted by Aristotle and passed to medieval and renaissance Europe. In a more concrete manner, however, the concept of aggregates or units of bonded atoms, i.e. "molecules", traces its origins to Robert Boyle 's 1661 hypothesis, in his famous treatise The Sceptical Chymist , that matter is composed of clusters of particles and that chemical change results from
6313-467: The hormone ghrelin in experiments to create an obesity vaccine. Immunizations are often widely stated as less risky and an easier way to become immune to a particular disease than risking a milder form of the disease itself. They are important for both adults and children in that they can protect us from the many diseases out there. Immunization not only protects children against deadly diseases but also helps in developing children's immune systems. Through
6420-581: The hydrogen molecule. Their valence bond treatment of this problem, in their joint paper, was a landmark in that it brought chemistry under quantum mechanics. Their work was an influence on Pauling, who had just received his doctorate and visited Heitler and London in Zürich on a Guggenheim Fellowship . Subsequently, in 1931, building on the work of Heitler and London and on theories found in Lewis' famous article, Pauling published his ground-breaking article "The Nature of
6527-400: The immune systems ability to replicate and elicits a response similar to natural infection. It is usually effective with a single dose. Examples of live, attenuated vaccines include measles , mumps , rubella , MMR , yellow fever , varicella , rotavirus , and influenza (LAIV). Passive immunization is where pre-synthesized elements of the immune system are transferred to a person so that
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#17328454746206634-735: The laws governing their structure and properties. In practice, however, this distinction is vague. In molecular sciences, a molecule consists of a stable system ( bound state ) composed of two or more atoms. Polyatomic ions may sometimes be usefully thought of as electrically charged molecules. The term unstable molecule is used for very reactive species, i.e., short-lived assemblies ( resonances ) of electrons and nuclei , such as radicals , molecular ions , Rydberg molecules , transition states , van der Waals complexes , or systems of colliding atoms as in Bose–Einstein condensate . Molecules as components of matter are common. They also make up most of
6741-597: The lives of thousands." Likewise, in the United States, the Continental Congress issued a proclamation in 1776 prohibiting Surgeons of the Army from performing inoculations. However, in 1777, George Washington , witnessing the virulent spread of smallpox, and fearing the likelihood of mass transmission of the disease throughout the Continental Army , weighed the risks and overruled this prohibition, conducting smallpox inoculation of all troops. He wrote, "Should
6848-404: The mass of a neutral carbon-12 ( C isotope ) atom. For network solids , the term formula unit is used in stoichiometric calculations. For molecules with a complicated 3-dimensional structure, especially involving atoms bonded to four different substituents, a simple molecular formula or even semi-structural chemical formula may not be enough to completely specify the molecule. In this case,
6955-476: The material has yang potency within it, so it remains active even after being kept from thirty to forty days. But in summer the yang potency will be lost in approximately twenty days. The best material is that which had not been left too long, for when the yang potency is abundant it will give a 'take' with nine persons out of ten people – and finally it becomes completely inactive, and will not work at all. In situations where new scabs are rare and
7062-525: The mid-twentieth century rituals of appeasement to Śītalā , the Indian goddess of smallpox, in Bengal. Early travellers to Ethiopia report that variolation was practiced by the Amhara and Tigray peoples . The first European to report this was Nathaniel Pearce , who noted in 1831 that it was performed by a debtera who would collect "a quantity of matter" from a person with the most sores from smallpox, then "cuts
7169-448: The minerals that make up the substance of the Earth, sand, clay, pebbles, rocks, boulders, bedrock , the molten interior , and the core of the Earth . All of these contain many chemical bonds, but are not made of identifiable molecules. No typical molecule can be defined for salts nor for covalent crystals , although these are often composed of repeating unit cells that extend either in
7276-400: The mortal part of every human and animal form; that the mediate (or second) acting cause, which stirs up the first, and throws it into a state of fermentation, is multitudes of imperceptible animalculae floating in the atmosphere; that these are the cause of all epidemical diseases, but more particularly of the small pox. Holwell ascribes this account to his Brahman informants. However, such
7383-537: The nature of molecules and their bonds began in the 17th century. Refined over time by scientists such as Robert Boyle , Amedeo Avogadro , Jean Perrin , and Linus Pauling , the study of molecules is today known as molecular physics or molecular chemistry. According to Merriam-Webster and the Online Etymology Dictionary , the word "molecule" derives from the Latin " moles " or small unit of mass. The word
7490-440: The nature of the interaction between the atoms, but only on the strength of the interaction. In fact, it includes weakly bound species that would not traditionally be considered molecules, such as the helium dimer , He 2 , which has one vibrational bound state and is so loosely bound that it is only likely to be observed at very low temperatures. Whether or not an arrangement of atoms is sufficiently stable to be considered
7597-576: The necessity of immunity through inoculation did not arise until those diseases were introduced in Europe. In January 1714 the Philosophical Transactions of the Royal Society published an account of a letter John Woodward had received from Emmanuel Timonius in Istanbul . Smallpox inoculation was advocated as a proven method of curbing the severity of the disease. The practice was introduced to England by Lady Mary Wortley Montagu . Lady Montagu's husband, Edward Wortley Montagu , served as
7704-517: The oceans and atmosphere. Most organic substances are molecules. The substances of life are molecules, e.g. proteins, the amino acids of which they are composed, the nucleic acids (DNA and RNA), sugars, carbohydrates, fats, and vitamins. The nutrient minerals are generally ionic compounds, thus they are not molecules, e.g. iron sulfate. However, the majority of familiar solid substances on Earth are made partly or completely of crystals or ionic compounds, which are not made of molecules. These include all of
7811-465: The pathogen). In health care, the main technique of artificial induction of immunity is vaccination , which is a major form of prevention of disease , whether by prevention of infection (pathogen fails to mount sufficient reproduction in the host), prevention of severe disease (infection still happens but is not severe), or both. Vaccination against vaccine-preventable diseases is a major relief of disease burden even though it usually cannot eradicate
7918-529: The people. The practice is documented in America as early as 1721, when Zabdiel Boylston , at the urging of Cotton Mather , successfully inoculated two slaves and his own son. Mather, a prominent Boston minister, had heard a description of the African practice of inoculation from Onesimus , an enslaved man in his household, in 1706 and later from Timoni's report to the Royal Society. However, Mather had been previously unable to convince local physicians to attempt
8025-402: The positive externality imposed by immunizations payments equal to the marginal benefit must be made. In countries like the United States these payment usually come in the form of subsidies from the government. Before 1962 immunization programs in the United States were run on the local and state level of governments. The inconsistency in subsidies lead to some regions of the United States reaching
8132-545: The procedure, yet his text did not give details on techniques of inoculation. Inoculation was first vividly described by Yu Chang in his book Yuyi cao (寓意草), or Notes on My Judgment , published in 1643. Inoculation was reportedly not widely practiced in China until the reign of the Longqing Emperor (r. 1567–1572) during the Ming dynasty (1368–1644), as written by Yu Tianchi in his Shadou Jijie (痧痘集解) of 1727, which he alleges
8239-478: The procedure. Following this initial success, Boylston began performing inoculations throughout Boston, despite much controversy and at least one attempt upon his life. The effectiveness of the procedure was proven when, of the nearly three hundred people Boylston inoculated during the outbreak, only six died, whereas the mortality rate among those who contracted the disease naturally was one in six. Boylston traveled to London in 1724. There he published his results and
8346-411: The rearrangement of the clusters. Boyle argued that matter's basic elements consisted of various sorts and sizes of particles, called "corpuscles", which were capable of arranging themselves into groups. In 1789, William Higgins published views on what he called combinations of "ultimate" particles, which foreshadowed the concept of valency bonds . If, for example, according to Higgins, the force between
8453-546: The regularity of repeating unit-cellular-structure that characterizes salts, covalent crystals, and metals. Molecules are generally held together by covalent bonding . Several non-metallic elements exist only as molecules in the environment either in compounds or as homonuclear molecules, not as free atoms: for example, hydrogen. While some people say a metallic crystal can be considered a single giant molecule held together by metallic bonding , others point out that metals behave very differently than molecules. A covalent bond
8560-430: The requirement great, it is possible to mix new scabs with the more aged ones, but in this case more of the powder should be blown into the nostril when the inoculation is done. Two reports on the Chinese practice were received by the Royal Society in London in 1700; one by Dr. Martin Lister who received a report by an employee of the East India Company stationed in China and another by Clopton Havers . But no action
8667-405: The same atoms in different arrangements are called isomers . Also carbohydrates, for example, have the same ratio (carbon:hydrogen:oxygen= 1:2:1) (and thus the same empirical formula) but different total numbers of atoms in the molecule. The molecular formula reflects the exact number of atoms that compose the molecule and so characterizes different molecules. However different isomers can have
8774-404: The same atomic composition while being different molecules. The empirical formula is often the same as the molecular formula but not always. For example, the molecule acetylene has molecular formula C 2 H 2 , but the simplest integer ratio of elements is CH. The molecular mass can be calculated from the chemical formula and is expressed in conventional atomic mass units equal to 1/12 of
8881-405: The same length and strength, which yields a molecular structure as shown below: The science of molecules is called molecular chemistry or molecular physics , depending on whether the focus is on chemistry or physics. Molecular chemistry deals with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics deals with
8988-568: The same time different biochemical activities. Molecular spectroscopy deals with the response ( spectrum ) of molecules interacting with probing signals of known energy (or frequency , according to the Planck relation ). Molecules have quantized energy levels that can be analyzed by detecting the molecule's energy exchange through absorbance or emission . Spectroscopy does not generally refer to diffraction studies where particles such as neutrons , electrons, or high energy X-rays interact with
9095-412: The scabs carefully in paper and put them into a small container bottle. Cork it tightly so that the activity is not dissipated. The container must not be exposed to sunlight or warmed beside a fire. It is best to carry it for some time on the person so that the scabs dry naturally and slowly. The container should be marked clearly with the date on which the contents were taken from the patient. In winter,
9202-438: The small inoculum, and the single point of initial infection, the resulting case of smallpox was generally milder than the naturally occurring form, produced far less facial scarring, and had a far lower mortality rate . As with survivors of the natural disease, the inoculated individual was subsequently immune to re-infection. In 1798, British physician Edward Jenner published the results of his experiments and thus introduced
9309-517: The smallest particles of pure chemical substances that still retain their composition and chemical properties. This definition often breaks down since many substances in ordinary experience, such as rocks , salts , and metals , are composed of large crystalline networks of chemically bonded atoms or ions , but are not made of discrete molecules. The modern concept of molecules can be traced back towards pre-scientific and Greek philosophers such as Leucippus and Democritus who argued that all
9416-493: The socially optimal quantity while other regions were left without subsidies and remained at the private marginal benefit level of immunizations. Since 1962 and the Vaccination Assistance Act , the United States as a whole has been moving towards the socially optimal outcome on a larger scale. Despite government subsidies it is difficult to tell when social optimum has been achieved. In addition to hardships determining
9523-410: The term may or may not include ions that satisfy this criterion. In quantum physics , organic chemistry , and biochemistry , the distinction from ions is dropped and molecule is often used when referring to polyatomic ions . A molecule may be homonuclear , that is, it consists of atoms of one chemical element , e.g. two atoms in the oxygen molecule (O 2 ); or it may be heteronuclear ,
9630-484: The transfer of microorganisms into and from laboratory apparatus such as test tubes and petri dishes in research and diagnostic laboratories, and also in commercial applications such as brewing, baking, oenology (wine making), and the production of antibiotics . For example, blue cheese is made by inoculating it with Penicillium roqueforti mold, and often certain bacteria. The term inoculate entered medical English through horticultural usage meaning to graft
9737-457: The true social marginal benefit of immunizations we see cultural movements shifting private marginal benefit curves. Vaccine controversies have changed the way some private citizens view the marginal benefit of being immunized. If Individual A believes that there is a large health risk, possibly larger than the antigen itself, associated with immunization they will not be willing to pay for or receive immunization. With fewer willing participants and
9844-652: The ultimate particle of oxygen and the ultimate particle of nitrogen were 6, then the strength of the force would be divided accordingly, and similarly for the other combinations of ultimate particles. Amedeo Avogadro created the word "molecule". His 1811 paper "Essay on Determining the Relative Masses of the Elementary Molecules of Bodies", he essentially states, i.e. according to Partington 's A Short History of Chemistry , that: The smallest particles of gases are not necessarily simple atoms, but are made up of
9951-409: The universe is composed of atoms and voids . Circa 450 BC Empedocles imagined fundamental elements ( fire ( [REDACTED] ), earth ( [REDACTED] ), air ( [REDACTED] ), and water ( [REDACTED] )) and "forces" of attraction and repulsion allowing the elements to interact. A fifth element, the incorruptible quintessence aether , was considered to be the fundamental building block of
10058-491: The use of immunizations, some infections and diseases have almost completely been eradicated throughout the World. One example is polio . Thanks to dedicated health care professionals and the parents of children who vaccinated on schedule, polio has been eliminated in the U.S. since 1979. Polio is still found in other parts of the world so certain people could still be at risk of getting it. This includes those people who have never had
10165-400: The use of vaccines as well as the use of antitoxin , which contains pre-formed antibodies such as to diphtheria or tetanus exotoxins . In nontechnical usage inoculation is now more or less synonymous with protective injections and other methods of immunization. Inoculation also has a specific meaning for procedures done in vitro (in glass, i.e. not in a living body). These include
10272-419: The vaccine, those who did not receive all doses of the vaccine, or those traveling to areas of the world where polio is still prevalent. Active immunization/vaccination has been named one of the "Ten Great Public Health Achievements in the 20th Century". Before the introduction of vaccines, people could only become immune to an infectious disease by contracting the disease and surviving it. Smallpox ( variola )
10379-432: The vaporization/sublimation of such materials does produce separate molecules where electrons are still transferred fully enough for the bonds to be considered ionic rather than covalent. Most molecules are far too small to be seen with the naked eye, although molecules of many polymers can reach macroscopic sizes, including biopolymers such as DNA . Molecules commonly used as building blocks for organic synthesis have
10486-521: The virus to reach levels of infection likely to kill the patient. The rising immunity terminates the infection. This ensures the less fatal form of the disease is the one caught, and gives the immune system the best start possible in combating it. Inoculation in the East was historically performed by blowing smallpox crusts into the nostril. In Britain, Europe and the American Colonies the preferred method
10593-436: Was based on Wang Zhangren's Douzhen Jinjing Lu (痘疹金鏡錄) of 1579. From these accounts, it is known that the Chinese banned the practice of using smallpox material from patients who actually had the full-blown disease of Variola major (considered too dangerous); instead they used proxy material of a cotton plug inserted into the nose of a person who had already been inoculated and had only a few scabs, i.e. Variola minor . This
10700-413: Was called cowpox inoculation or vaccine inoculation (from Latin vacca = cow). Smallpox inoculation continued to be called variolation, whereas cowpox inoculation was called vaccination (from Jenner's term variolae vaccinae = smallpox of the cow). Louis Pasteur proposed in 1861 to extend the terms vaccine and vaccination to include the new protective procedures being developed. Immunization refers to
10807-459: Was called "to implant the sprouts", an idea of transplanting the disease which fit their conception of beansprouts in germination . Needham quotes an account from Zhang Yan's Zhongdou Xinshu (種痘新書), or New book on smallpox inoculation , written in 1741 during the Qing dynasty (1644–1912), which shows how the Chinese process had become refined up until that point: Method of storing the material. Wrap
10914-516: Was elected to the Royal Society in 1726. In France , considerable opposition arose to the introduction of inoculation, and it was banned by the Parlement . Voltaire , in his Lettres Philosophiques , wrote a criticism of his countrymen for being opposed to inoculation and having so little regard for the welfare of their children, concluding that "had inoculation been practised in France it would have saved
11021-516: Was learning the Dalton hook-and-eye bonding method , which was the mainstream description of bonds between atoms at the time. Pauling, however, was not satisfied with this method and looked to the newly emerging field of quantum physics for a new method. In 1926, French physicist Jean Perrin received the Nobel Prize in physics for proving, conclusively, the existence of molecules. He did this by calculating
11128-445: Was prevented in this way by inoculation , which produced a milder effect than the natural disease. The first clear reference to smallpox inoculation was made by the Chinese author Wan Quan (1499–1582) in his Douzhen xinfa (痘疹心法) published in 1549. In China, powdered smallpox scabs were blown up the noses of the healthy. The patients would then develop a mild case of the disease and from then on were immune to it. The technique did have
11235-444: Was rubbing material from a smallpox pustule from a selected mild case ( Variola minor ) into a scratch between the thumb and forefinger. This would generally be performed when an individual was in normal good health, and thus at peak resistance. The recipient would develop smallpox; however, due to being introduced through the skin rather than the lungs, and possibly because of the inoculated individual's preexisting state of good health,
11342-413: Was taken. According to Voltaire (1742), the Turks derived their use of inoculation from neighboring Circassia . The Circassian women have, from time immemorial, communicated the small-pox to their children when not above six months old by making an incision in the arm, and by putting into this incision a pustule, taken carefully from the body of another child. This pustule produces the same effect in
11449-417: Was through the air, invading the mucous membranes of the mouth, nose, or respiratory tract, before migrating throughout the body via the lymphatic system , resulting in an often severe disease. In contrast, infection of the skin usually led to a milder, localized infection – but, crucially, still induced immunity to the virus. This first method for smallpox prevention, smallpox inoculation,
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