Mayow, John (DNB00)

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MAYOW, MAYOUWE, or MAYO, JOHN (1640–1679), physiologist and chemist, ‘descended from a genteel family of his name living at Bree in Cornwall’ (Wood), was son of William and Elizabeth Mayow. Born on 24 May 1640 (Sloane, 1708, f. 117) in the parish of St. Dunstan-in-the-West, London, he was received as commoner of Wadham College, Oxford, 3 April 1658, and admitted scholar 23 Sept. 1659. On the recommendation of Henry Coventry (1619–1686) [q. v.], who was a former fellow of the college, he was elected on 3 Nov. 1660 (Gardiner, Registers of Wadham) to a fellowship at All Souls' College. He graduated B.C.L. 30 May 1665, and D.C.L. 5 July 1670. Mayow obtained the further privilege of studying physic, which exempted him from taking holy orders. It is probable that he was a pupil of Thomas Willis [q. v.], Sedleian professor of natural philosophy, whom he treated in controversy with especial respect, and he certainly came into contact with Richard Lower [q. v.], who was working with Willis.

Mayow practised medicine at Bath in the summer season, and made a careful chemical study of the Bath waters, and published the results as a chapter of his tract ‘De Sal-Nitro’ (cf. his Tractatus Quinque). One of his rivals, Dr. Thomas Guidott [q. v.] , denounced his chief conclusions in his ‘Discourse of Bathe,’ 1676, and suggested at the same time that Mayow had ‘ploughed with his heifer’ (Discourse, p. 12). Mayow was elected F.R.S. 30 Nov. 1678, on the proposition of Hooke, a fact of some importance in connection with the bitter charge of plagiarism made against him by Thomson (Hist. of the Royal Society, p. 467). That there is much in common between the fundamental ideas of Hooke (Micrographia, 1665, p. 103) and of Mayow with regard to combustion is undeniable, although the two men approached the subject in very different ways; but it must be noted that Hooke brought no charge in this connection against Mayow, and maintained friendly relations with him. ‘He died,’ says Wood, ‘in an apothecaries house bearing the sign of the Anker, in York Street, Covent Garden (having a little before been married, not altogether to his content).’ He was buried in the church of St. Paul, Covent Garden, 10 Oct. 1679. Prefixed to the ‘Tractatus quinque’ is a fine engraved portrait of Mayow. The face is long and thin, the features, and especially the mouth, delicately moulded and expressive.

In 1668 Mayow published his ‘Tractatus duo, de Respiratione et de Rachitide,’ Oxford, 8vo. The second tract, purely medical, was not of great importance; the subject of the first determined the work of Mayow's life. They were republished at Leyden in 1671, and an English translation of ‘De Rachitide,’ by W. Tury, appeared under the title Rhachitidologia at Oxford, in 1685. The two tracts were meanwhile republished at Oxford in 1674 (with the vice-chancellor's imprimatur, 17 July 1673), together with three fresh essays under the title, ‘Tractatus quinque Medico-Physici,’ 8vo. The book was dedicated, with a grateful and characteristic preface, to his patron, Coventry, and abstracts were published in the ‘Philosophical Transactions of the Royal Society.’ The ‘Tractatus quinque’ were republished at the Hague in 1681, 8vo, under the title ‘Opera Omnia,’ and at Geneva in 1685. They were translated into Dutch (1684), German (1799), and French (1840).

From the ‘numerosa scriptorum turba’ of his time Mayow at the outset chooses Descartes as his master in method. He takes his facts from great observers like Boyle, Malpighi, Steno, Willis, and Lower, but above all from personal observation. In the tract on ‘Respiration’ (1668) he described its mechanism, with the movement of ribs and diaphragm, almost as perfectly as can be done to-day (Heidenhein). He made the capital discovery of the double articulation of the ribs with the spine, and put forward views with regard to the function of the internal intercostals which are still under discussion. The function of breathing is merely, he says, to bring air in contact with the blood, to which it gives up its nitroaerian constituent (oxygen), and from which it carries off the vapours produced by the heating of the blood. He shows that the heart cannot be dilated by the blood fermenting in its cavity (Descartes), but that it is a muscle, whose function is to drive the blood through the lungs and over the body, a view proved experi- mentally in the following year by Lower (De Corde, 1669). The blood carries the nitroaerian constituent to the muscles, and their motion results from the chemical reaction (fermentation) in the muscle with the combustible matter contained therein. The heart, like any other muscle, ceases to act when the nitroaerian particles are no longer supplied to it.

In the ‘Tractatus quinque’ the subject of the earlier work is developed and treated from a higher point of view, and carefully tested in many details. The chemistry of burning is studied separately before being applied to physiology. The treatise ‘On Saltpetre and the Nitroaerian Spirit’ develops a theory of combustion on lines closely resembling those followed by Lavoisier in the next century. Saltpetre is recognised as containing a base and an acid, and the acid part is formed from one of the constituents of the air, its nitroaerian particles, the air being composed of these and of another gas, left after combustion and respiration. To produce combustion sulphureous, i.e. inflammable, matter must come into contact with the nitroaerian particles. When antimony is calcined its increase in weight is due to the fixation of these particles; the rusting of metals and the conversion of iron pyrites into a vitriol are due to the same cause. It is too much to say, as some have done, that Mayow proves his case fully. The best evidence of his mental calibre is that he himself distinguishes everywhere between his facts and the hypothesis which he seeks to establish. But the logical consequences of his hypothesis he developes with the greatest acuteness. He is, it is true, misled by the desire to explain everything mechanically (which has dominated physical science since Descartes) into long and useless speculations with regard to the elasticity of the air and of solid bodies, the nature of light and of the sun, &c. But whenever he sees a way of submitting his ideas to the test of experiment, he does so. He proves that a candle burning and a mouse breathing in a closed space act in precisely the same way on the air contained, and diminish its volume and alter its properties. The failure to grasp the notion of compound gases is his true stumbling-block. Yet he recognises the fact that different gases (e.g. air and nitric oxide) exist, and carefully shows that they all follow Boyle's law.

The older tract, ‘De Respiratione,’ revised, follows ‘De Sal-Nitro,’ and Mayow next extends his explanation of respiration to the fœtus and the egg. The maternal blood supplies the fœtus not only with nutrition, but with oxygen. The egg, he thinks, contains sufficient air for itself, and probably this air is itself ‘pure or vital air,’ and not ordinary air. Moreover, as the egg is kept warm and the chick does little work, it needs little respiration. In the tract on ‘Muscular Motion and Animal Spirits’ he comes to the conclusion that the nitroaerian particles must be identified with the animal spirits of his contemporaries, and that they are separated from the blood in the brain, and thence travel along the nerves to the muscles, where they combine with the combustible matter and cause the muscle to contract by the vehement motion set up in the fibres; an important modification of Descartes's theory. The animal spirits, he declared, must not be confounded with the universal sensitive soul. In the course of the five treatises the most various points are touched on, including the theory of the relation of the saltpetre in the soil with plants (De Sal-Nitro, p. 52); the remarkably lucid theory of chemical affinity (idem, p. 242); and the mechanical explanation of the act of jumping (De Motu Musculari, p. 100).

Mayow stands immeasurably above such men as Willis and Sylvius, with their medley of half-digested Cartesianism and iatrochemistry. He must be classed with Hooke and Boyle, possessing the scientific imagination of the one, the tenacity of the other, and succeeding where Boyle failed. He had the genius to perceive exactly the problems which must be solved before any great advance in chemistry or physiology could be made, to guess at and partly to discover their solutions; and he showed a critical faculty in theory and experiment that is not to be met with in these two sciences until we come to Lavoisier. His premature death retarded the advent of modern chemistry for more than a century (Hoffer, Hist. de la Chimie, ii. 262).

By his chief contemporaries, save possibly Lower, Mayow's work met with little understanding; several, like Pechlin, borrow his language, but neither grasp his ideas nor even mention his name. The anatomical discovery with regard to the ribs was alone definitely adopted by the text-books (S. Collins, Systeme of Anatomy, 1685, pp 826, 833, 837). It is noteworthy that Stephen Hales [q. v.] repeated some of Mayow's experiments on combustion (Vegetable Staticks, 1727, i. 230 et seq.). As soon as Priestley had discovered oxygen, Mayow's works were disinterred. Blumenbach gives them high praise (Institutiones Physiologicæ, 1786, p. 114), and he was followed by Yeats, Beddoes, Fourcroy, J. A. Scherer, and A. N. Scherer, who are as a rule more enthusiastic than critical. The development of modern ideas with regard to muscular action again drew attention to Mayow (R. Heidenhain, Mechanische Leistung, 1864, p. 8; A. Gamgee, Physiological Chemistry, i. 407).

An engraved portrait is prefixed to Mayow's ‘Tractatus Quinque.’

[Besides the sources already quoted: Wood's Athenæ Oxonienses, 1st ed. ii. 474, and ed. Bliss, iii. 1199, and Fasti, ii. 281; Registers of the parishes of St. Dunstan-in-the-West and St. Paul's, Covent Garden; Gardiner's Registers of Wadham College; Catalogue of Library of Royal College of Surgeons; Birch's History of the Royal Society, iii. 384, 442; Jöcher's Gelehrten-Lexicon, 1751, iii. 333; J. N. Pechlin's De aeris et alimenti defectu, 1676, p. 142; G. F. Rodwell, ‘On the supposed Nature of Air prior to the Discovery of Oxygen,’ Chemical News, xii. 293, xiv. 51; Cuvier's Histoire des Sciences Naturelles, ii. 357–9; Burrows's Worthies of All Souls', p. 204; Gmelin's Geschichte der Chemie, 1798, ii. 112; Hoefer's Histoire de la Chimie and Nouvelle Biographie; Kopp's Geschichte der Chemie, passim, and Beiträge, &c.; K. Sprengel's Geschichte der Arzneykunde, passim; G. D. Yeats's Claims of the Moderns to some Discoveries in Chemistry, 1780; T. Beddoes's Chemical Experiments and Opinions (of Mayow), 1793; J. A. Scherer's Beweis dass J. Mayow vor hundert Jahren den Grund zur antiphlogistischen Chemie u. Physiologie gelegt hat; J. Koellner's Mayow's Schriften aus dem Lateinischen übersetzt nebst einer Vorrede von A. N. Scherer; private information from Dr. L. Larmath and Mr. C. W. C. Oman.]

P. J. H.