228 The Rise of the Modern [lect. 



matters which were the subjects of his own original investi- 

 gations. 



In his third volume, which is devoted to respiration, Haller 

 begins the subject with an account of the thorax and its 

 contents, and of the actions and uses of the various parts. 

 Then follows a discussion of the physical properties of air, 

 its weight and its ' spring.' In the course of this he dwells on 

 the causes which destroy the 'spring' of air, noting as chief 

 among these the respiration of animals, and observing that 

 while this loss of 'spring' seems to be intimately connected 

 with the fact that animals cannot live in air which is not 

 renewed, the exact cause why they cannot do so is by no 

 means clear. Next, after an exposition of the general pheno- 

 mena and of the more mechanical problems of respiration, he 

 comes to the use of breathing and asks the question, Why 

 almost all animals stand in need of air ? This leads to the 

 question, Whether air enters into and is mixed with the blood 

 in breathing ? In respect to this he quotes three leading 

 opinions. 



" From the most ancient times it has been a common view 

 " that as air is in nature the cause of almost all movement and 

 " without it fire cannot subsist or charcoal take fire, so also air 

 " enters into the vital humours of animals and provides in them 

 " that which brings about life. Very many are the authors who 

 " have approved of this view, among whom I will only mention 

 " the chief, and of these the more recent, who have maintained 

 " that the very air of the atmosphere itself, such as we take in 

 " by the mouth, reaches the blood. A different opinion is held by 

 " those who have admitted that only a something reaches the 

 " blood from the air, which something some have spoken of as 

 " the more subtle particles or ether, others again as aereal nitre. 

 " A third party have maintained that the very air itself reaches 

 " the blood but air dissolved in water and deprived of its elastic 

 " force so that it cannot expand or undergo compression." 



In discussing these several views Haller naturally dwells 

 upon the corresponding views held as to the use or function of 

 the air or part of the air thus reaching the blood. He speaks 

 of what may be called the physical hypothesis, such as that held 



