vn] , of the Seventeenth Century. 199 



occurrence of muscular contractions, it was essential in the 

 brain to the development of animal spirits. 



This great truth was reached at a time when the men of 

 chemistry were struggling with the spiritualistic fermentations 

 of van Helmont on the one hand, and with the material 

 effervescences of Sylvius on the other. It was reached by a 

 young man of twenty-five years, who died a few years afterwards. 



When we look at the portrait affixed to his book 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. His premature death bids us think that 

 not long after he had made known the results of the labour of 

 his early years, the beginnings of disease had already made his 

 spirits droop and his hand hang heavy by his side. Otherwise 

 he must have had something to say during the ten years which 

 ran between the publication of his book and his death. Yet he 

 was silent. 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. This bright school of English physio- 

 logists of the mid-seventeenth century, Boyle, Hooke, Lower, 

 and Mayow, worthy children of the great Harvey, passed away, 

 and for a long time none took their place. Though the physical 

 and experimental work of the three former remained effective 

 on men's minds, the chemical work of Mayow soon passed out 

 of ken ; a few passing references, and those for the most part 

 feathered with scorn, to the supposed part played by nitrous 

 particles in breathing, supply all that can be found in succeeding 

 writers. The world had to wait for more than a hundred years 

 till Mayow's thought arose again as it were from the grave in a 

 new dress, and with a new name ; and that which in the first 

 years 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. 



