I 4 RESPIRATION 



From the foregoing review of the knowledge existing up to 

 the beginning of the present century on the physiological regu- 

 lation of breathing it will be seen that the conclusions reached 

 were unsatisfactory in many ways, and to some extent contra- 

 dictory. On the one hand the nervous regulation through the vagi 

 and other nerves seemed to have no relation to the requirements 

 of the body for oxygen and for removal of CO 2 , and in fact to 

 act antagonistically to these requirements. On the other hand 

 the excitation of the breathing during muscular work seemed 

 also, from the results of Geppert and Zuntz, to have no definite 

 relation to increased requirements for oxygen and CO 2 . There 

 was also no definite quantitative information as to why in normal 

 breathing during rest the composition of the expired air is so 

 constant as it is. Without more exact and consistent physiological 

 knowledge it appeared to be very difficult to interpret the ab- 

 normal breathing so often met with in disease, or to know how to 

 set about investigating it. 



From still another standpoint the existing knowledge was very 

 unsatisfactory to me personally. From a consideration of the 

 general characteristics which distinguish a living organism from 

 a machine I had become convinced that a living organism cannot 

 be correctly studied piece by piece separately as the parts of a 

 machine can be studied, the working of the whole machine being 

 deduced synthetically from the separate study of each of the parts. 

 A living organism is constantly showing itself to be a self-main- 

 taining whole, and each part must therefore always be behaving 

 as a part of such a self-maintaining whole. In the existing 

 knowledge of the physiology of breathing this characteristic could 

 not be clearly traced. The regulation of breathing did not, as 

 represented in the existing theories, appear to be determined in 

 accordance with the requirements of the body as a whole; and 

 for this reason I doubted the correctness of these theories, and 

 suspected that errors had arisen through the mistake of not study- 

 ing the breathing as one of the coordinated activities of the whole 

 body. In so far as the investigations detailed in succeeding chap- 

 ters originated with me, they were mainly inspired by the con- 

 siderations just mentioned; and, as will be seen in the sequel, the 

 same considerations have led to a reinvestigation and reinterpre- 

 tation of other physiological activities besides breathing. 



