MAYOW 45 



aereal particles during the calcination. As we shall see more than a 

 century later Lavoisier arrives at the same conclusion.. But Mayow 

 did not stop here. He proceeded to point out the identity of burning 

 and breathing: 



"If a small animal and a lighted candle be shut up in the same vessel, the 

 entrance into which, of air from without is prevented, you will see in a short 

 time, the candle go out; nor will the animal long survive its funeral torch. 

 Indeed, I have found by observation that an animal shut up in a flask together 

 with a candle will continue to breathe for not much more than half the time 

 than it otherwise would, that is without the candle. * * * The reason why the 

 animal can live some time after the candle has gone out seems to be as follows: 

 The flame of the candle needs for its maintenance a continuous and at the same 

 time a sufiiciently full and rapid stream of nitro-aereal particles. Whence it 

 comes about that if the succession of nitro-aereal particles be interrupted, even 

 for a moment, or if these are not supplied in adequate quantity, the flame pres- 

 ently sinks and goes out. Hence, so soon as the igneo-aereal particles begin to 

 reach the flame scantily and slowly, it is soon extinguished. For animals, on 

 the other hand, a lesser store of the aereal food is sufficient, and one supplied at 

 intervals, so that the animal can be sustained by aereal particles remaining after 

 the candle has gone out. Hence it may be remarked that the movements of the 

 collapsed lungs not a little help towards the sucking of the aereal particles 

 which may remain in the said flask, and towards transferring them into the 

 blood of the breathing animal. Whence it comes about that the animal does not 

 perish until just before the aereal particles are wholly exhausted. * * * We may 

 infer that animals and fire deprive the air of particles of the same kind." 



Mayow's account of the mechanics of respiration would need lit- 

 tle or no revision for a modem text book on physiology. He showed 

 that the air entered the lungs during respiration solely by atmospheric 

 pressure. He makes use of the experiment whereby a collapsed 

 bladder is placed into a bell- jar, the bladder expanding as the air in 

 the jar is exhausted by means of an air pump. He taught that in in- 

 spiration the chest is enlarged by the descent and contraction of the 

 diaphragm and by the raising of the ribs. Mayow further tackles 

 the raison d'etre of breathing in which he shows that something 

 necessary to sustain life passes from the air into the blood. "We 

 have no right," said he, "to deny the entrance of air into the blood 

 because on account of the bluntness of our senses we cannot actually 

 see the vessels by which it makes its entrance." 



These extracts go to show how mature the views of the seven- 

 teenth century school of English physiologists, Boyle, Hooke, Lower /^ 

 and Mayow in particular, were. Mayow by his nitro-aereal or igneo- ^ 

 aereal substance evidently meant oxygen. Their work was, however, 

 allowed to slumber, until the scientific path was retraveled by their 

 successors nearly a century later. 



Summary ^rior to the Beginning of the Eighteenth Century. — 

 Vto H5hnont^(1648) had discovered some of the properties of car- 

 bohdioxide. lie showed that a gas was formed from fermentation 

 or the combustion of carbon and from the action of vinegar on cer- 

 tain carbonates, and that this gas was incapable of supporting com- 

 bustion. Boyle (1670), as we have seen, proved that air was neces- 

 sary to ^e life of all animals, even those which lived under water. 

 Bernoulli, j at a later date, showed that the existence of aquatic ani- 

 ^ale depended upon air held in solution in water. Hooke exposed 



