1912] Chemical Interpretation of Vital Phenomena. 269 



THE CHEMICAL INTERPRETATION OF VITAL PHENOMENA. 



By J. B. Leathes, M.A., F.R.S. 

 Professor of Pathological Chemistry in the University of Toronto. 



{Read 20th April, igi2.) 



There are many natural phenomena which everyone recognizes as 

 falling within the legitimate province of chemical interpretation, but it 

 is only within the last hundred years or so that anyone but the alchem- 

 ists have included among them phenomena of life, and even now the 

 cliam of chemists to interpret these is conceded grudgingly by those who 

 are in sympathy with the aspirations of Science, and by the rest of the 

 world is looked upon with something of the horror and the suspicion 

 in which the chemists of the Middle Ages practised their arts. 



There are perhaps three moments in the history of modern chem- 

 istry at which we may recognize this claim clearly pronounced for ears 

 that hear through the clamour of scientific pretensions: and the first is 

 at the very hour of its birth. In the ten years preceding the outbreak 

 of the French Revolution a number of experiments were designed and 

 carried out by the Baptist of this science, Lavoisier, in some of which he 

 had the assistance of another French genius of the day, Laplace. These 

 experiments were the prototypes of investigations that have ever since 

 been carried on along essentially the lines marked out by Lavoisier 

 himself. A sparrow enclosed in a bottle was found to die in less than an 

 hour; while animals in a similarly confined space, if provision was made 

 for the absorption of carbonic acid by potash and a sufificient supply of 

 oxygen was given, lived comfortably. In another set of experiments a 

 stream of air was passed through a vessel in which an animal was placed, 

 the escaping air collected and the amount of water and carbonic acid 

 that it contained determined. And similar determinations were carried 

 out in experiments on man, a mask being used with valves arranged so 

 that the air inspired came from the free air of the room, but that which 

 was expired was delivered into a vessel where it could be measured and 

 analyzed. 



Experiments of these three types have been repeated with more 

 elaborate apparatus almost continuously since that time. The first 

 method was that employed in the important work of Regnault and Reiset 

 in the middle of the last century; and as recently as twenty years ago a 

 large apparatus on this principle was constructed by Hoppe Seyler at 

 Strassburg for the study of respiratory exchange in man. The second 



