John Mayow FRS

Royal Society

The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

 (1641–1679) was a chemist

Chemist

A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

, physician

Physician

A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

, and physiologist who is remembered today for conducting early research into respiration and the nature of air. Mayow worked in a field that is sometimes called pneumatic chemistry

Pneumatic chemistry

Pneumatic chemistry is a term most-closely identified with an area of scientific research of the seventeenth, eighteenth, and early nineteenth centuries. Important goals of this work were an understanding of the physical properties of gases and how they relate to chemical reactions and,...

.

Life

There has been controversy over both the location and year of Mayow's birth, with both Cornwall

Cornwall

Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...

 and London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 claimed, along with birth years from 1641 to 1645. Proctor's extensive research led him to conclude that Mayow was born in 1641 near Morval in Cornwall and that he was admitted to Wadham College, Oxford

Wadham College, Oxford

Wadham College is one of the constituent colleges of the University of Oxford in the United Kingdom, located at the southern end of Parks Road in central Oxford. It was founded by Nicholas and Dorothy Wadham, wealthy Somerset landowners, during the reign of King James I...

 at age 17 in 1658. A year later Mayow became a scholar at Oxford, and in 1660 he was elected to a fellowship at All Souls

All Souls College, Oxford

The Warden and the College of the Souls of all Faithful People deceased in the University of Oxford or All Souls College is one of the constituent colleges of the University of Oxford in England....

. He graduated in law

Law

Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

 (bachelor, 1665, doctor, 1670), but made medicine his profession, and became noted for his practice - therein, especially in the summer time, in the city of Bath. In 1678, on the proposal of Robert Hooke

Robert Hooke

Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...

, Mayow was chosen a fellow of the Royal Society

Royal Society

The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

. The following year, after a marriage which was not altogether to Mayow's content, he died in London and was buried in the Church of St. Paul, Covent Garden.
Scientific work

Mayow published at Oxford in 1668 two tracts, on respiration

Respiration (physiology)

'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...

 and rickets

Rickets

Rickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D, magnesium , phosphorus or calcium, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries...

, and in 1674 these were reprinted, the former in an enlarged and corrected form, with three others De sal-nitro et spiritu nitro-aereo, De respiratione foetus in utero et ovo, and De motu musculari et spiritibus animalibus as Tractatus quinque medico-physici. The contents of this work, which was several times republished and translated into Dutch

Dutch language

Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

, German

German language

German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....

 and French

French language

French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

, show him to have been an investigator much in advance of his time.

Accepting as proved by Boyle

Robert Boyle

Robert Boyle FRS was a 17th century natural philosopher, chemist, physicist, and inventor, also noted for his writings in theology. He has been variously described as English, Irish, or Anglo-Irish, his father having come to Ireland from England during the time of the English plantations of...

's experiments that air is necessary for combustion

Combustion

Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

, Mayow showed that fire is supported not by the air as a whole but by a more active and subtle part of it. This part he called "spiritus igneo-aereus," or sometimes "nitro-aereus", for he identified it with one of the constituents of the acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

 portion of nitre (now called potassium nitrate, KNO₃) which he regarded as formed by the union of fixed alkali

Alkali

In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

 with a spiritus acidus. In combustion the particulae nitro-aereae – either pre-existent in the thing consumed or supplied by the air – combined with the material burnt; as Mayow inferred from his observation that antimony, strongly heated with a burning glass, undergoes an increase of weight which can be attributed to nothing else but these particles.

Mayow argued that the same particles are consumed in respiration, because he found that when a small animal and a lighted candle were placed in a closed vessel full of air the candle first went out and soon afterwards the animal died. However, if there was no candle present the animal lived twice as long. He concluded that this constituent of the air is absolutely necessary for life, and supposed that the lungs separate it from the atmosphere and pass it into the blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

. It is also necessary, Mayow inferred, for all muscular movements, and he thought there was reason to believe that the sudden contraction of muscle

Muscle

Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

 is produced by its combination with other combustible (salino-sulphureous) particles in the body; hence the heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

, being a muscle, ceases to beat when respiration is stopped. Animal heat also is due to the union of nitro-aerial particles, breathed in from the air, with the combustible particles in the blood, and is further formed by the combination of these two sets of particles in muscle during violent exertion.

In effect, therefore, Mayow – who also gives a remarkably correct anatomical description of the mechanism of respiration – preceded Priestley

Joseph Priestley

Joseph Priestley, FRS was an 18th-century English theologian, Dissenting clergyman, natural philosopher, chemist, educator, and political theorist who published over 150 works...

 and Lavoisier

Antoine Lavoisier

Antoine-Laurent de Lavoisier , the "father of modern chemistry", was a French nobleman prominent in the histories of chemistry and biology...

 by a century in recognizing the existence of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

, under the guise of his "spiritus nitro-aereus," as a separate entity distinct from the general mass of the air. Mayow perceived the part "spiritus nitro-aereus" plays in combustion and in increasing the weight of the calces (oxides) of metals as compared with metals themselves. Rejecting the common notions of his time that the use of breathing is to cool the heart, or assist the passage of the blood from the right to the left side of the heart, or merely to agitate it, Mayow saw in inspiration a mechanism for introducing oxygen into the body, where it is consumed for the production of heat and muscular activity. He even vaguely conceived of expiration as an excretory process. Using bell-jars over water Mayow showed that the active substance that we today call oxygen constitutes about a fifth part of the air.

Parts of Mayow's work seems to agree with modern ideas regarding air and combustion. Mayow noted, as had others before him, that some materials gain weight on strong heating. Antoine Lavoisier (1743–1794) and others later interpreted this gain in terms of a reaction with a gaseous material (oxygen) in the air. See Holmyard and others for critiques of Mayow's work and comparisons to modern chemical thought.
Further reading

- The above originally was published in 1674.

- See especially chapters 7 - 9 on Mayow's life, work, and influence.