ORGANIC DETERMINATION 85 



the progress of our knowledge in relation to 

 the regulation of breathing. 



From the earliest times it was of course 

 known that in all the higher animals breathing 

 is an essential part of organic activity, as 

 mechanical stoppage of the breathing causes 

 rapid death. Very little further was known, 

 however, until the time of Black, Priestley, 

 and Lavoisier, although Mayow, the funda 

 mental importance of whose work was not at 

 the time appreciated, had in reality come very 

 close to modern ideas. With a single flash 

 the whole subject was illuminated by the 

 definite discovery of oxygen and carbon 

 dioxide and their relation to respiration. 

 Henceforth we knew that the necessity for 

 breathing, and the regulation of breathing, is 

 bound up with the necessity for absorbing 

 oxygen and giving off carbon dioxide. Breath 

 ing is of fundamental physiological importance, 

 because the consumption of oxygen and re 

 moval of carbon dioxide are fundamental 

 organic activities in animals. 



Assuming that an organism is an organ 

 ism, and not a mere machine, we should 

 expect to find that these activities are organi- 



