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water, or an animal breathing under the same conditions, equally cause 

 a diminution in the volume of the air more, indeed, in amount when 

 an animal is thus suffocated than when the candle goes out. 



It may thus be taken that Mayow grasped the first factor of the 

 process of external respiration, viz., that something is taken from the 

 air by the blood. We have to wait a little longer before the know- 

 ledge of the second factor is fully discovered, viz., that the blood 

 gives off something to the air in the lungs. Even Hales expresses the 

 view that the expired air contains aqueous vapour and certain 

 noxious effluvia, and has its spring diminished, a view endorsed by 

 Haller. 



" If a small animal and a lighted candle be placed in a closed flask, so that no air 

 can enter, in a short time the candle will go out, nor will the animal long survive. 

 . . . . The animal is not suffocated by the smoke of the candle. . . . The 

 reason why the animal can live some time after the candle has gone out seems to be that 



the flame needs a continuous rapid and full supply of nitro-aereal particles 



For animals, a less aereal spirit is sufficient. . . . The movements of the lungs help 

 not a little towards sucking in aereal particles which may remain in said flask and 

 towards transferring them to the blood of the animal." (Mayow.) 



The hypothesis of Mayow as to the constitution of the atmo- 

 sphere seems at first to have attracted considerable attention, but it 

 was shortly afterwards abandoned or forgotten. Two quotations will 

 suffice : 



" The total neglect into which the experiments of Mayow had fallen, during the 

 greater part of the last century, must be regarded as a very singular occurrence in the 

 history of science. . . . Mayow was a man of extraordinary genius, and one who, 

 on many points, far outstripped the science of his age. . . . He saw the analogy of 

 respiration to combustion, as well as the connection which subsists between these 

 processes and one of the constituents of the atmosphere." (John Bostock, Physiology, 

 3rd ed. 1836.) 



" When we look at his portrait we see a face delicate in outline, yet with a firm 

 mouth, the visage of a man who had spent his as yet short days in the quiet but earnest 

 and unresting pursuit of truth amid the calm of academic retirement. . . . Had 

 his body been as strong as his mind was acute, had he lived to that ripe old age which 

 was reached by many another leader in science, how different had been the story of 

 chemical physiology ! " " But it was not to be. . . The world had to wait for more than 

 a hundred years, till Mayow's thought rose again as it were from the grave in a new dress, 

 and with a new name ; and that which in the first year of the latter half of the 

 seventeenth century, as igneo-aereal particles, shone out in a flash and then died away 

 again into darkness, in the last years of the eighteenth century, as oxygen, lit a light 

 which has burned, and which has lighted the world with increasing steadiness, up to the 

 present day." (M. Foster, Lectures on the History of Physiology, 1901.) 



Of CHEMICAL LEARNING, in the real sense of the word, there was 

 none until after the time when Harvey taught. Towards the end of 

 the fifteenth century there lived in Erfurt a Benedictine monk, one 

 BASIL VALENTINE, and an alchemist withal, who introduced the 

 idea of an archceusor rather a variety oiarchcei as the dominant directive 



M 



