76 



SCIENCE 



[N. S. Vol. XL VI. No. 1178 



This department of science has developed 

 independently, and only in recent years can 

 its influence upon the older science of 

 physiology be detected. The physiologists, 

 in their more abstract and more analytical 

 researches have usually dealt exclusively 

 with physical and chemical phenomena. 

 Unlike Eoux's followers, they have been 

 concerned with those things which are or- 

 ganized in the living being, rather than 

 with the organization of them. Their very 

 method of research, which proceeds from a 

 preliminary anal3'sis of the factors of or- 

 ganization, has obscured the larger biolog- 

 ical problem. 



At length Pavlov's researches on the 

 glands of digestion, the study of internal 

 secretions and hormones, Sherrington's 

 investigation of the integrative action of 

 the nervous system, Cannon's study of the 

 emotions, and many other independent 

 lines of investigation have cleared the 

 ground, and at the present moment the 

 physico-chemical treatment of the problem 

 of organization is widely, if somewhat 

 vaguely, recognized as the ultimate goal of 

 physiological research. An interesting 

 statement of the present condition of 

 physiology in this respect may be found in 

 Haldane's little book "Mechanism, Life 

 and Personality. " It is doubtful, however, 

 if all the philosophical conclusions that Hal- 

 dane draws can be regarded as well 

 founded. 



In the study of metabolism, which has 

 also had an independent development, the 

 idea of organization has long dominated re- 

 search. This is due to the fact that here 

 the concept of equilibrium can not be 

 avoided. At an early period in the history 

 of the science it was discovered that a nor- 

 mal organism is in a state of nitrogen 

 equilibrium. That is to say, the composi- 

 tion, in respect of compounds of nitrogen, 

 is steadily preserved, through the regula- 

 tion of a long chain of intricate chemical 



processes. Day by day the ingestion of 

 nitrogen is approximately equal to the ex- 

 cretion. A modification of the diet may 

 cause a temporary disturbance of the con- 

 dition, but this is soon restored. The phe- 

 nomena of growth and disease are found to 

 involve more enduring changes. Hereupon 

 by a process of reasoning patterned upon 

 that of physical science, growth is declared 

 to involve nothing more than other phe- 

 nomena superimposed upon the underlying 

 conditions, thereby modifying the observed 

 facts in such manner that the fundamental 

 state is partly obscured. And disease is 

 after all, in its very essence, a disturbance 

 of organization ; in short, diseases of meta- 

 bolism involve by definition disturbances of 

 equilibria, which may or may not be com- 

 pensated. 



Further research reveals similar equi- 

 libria concerning carbon, sulphur, phos- 

 phorus and the other elements. The results 

 are extended to definite chemical compounds 

 such as water, salt, sodium bicarbonate, 

 glucose and the like. It is perceived that 

 the equilibria of temperature, of volume, of 

 alkalinity, which involve physico-chemical 

 states, are truly analogous phenomena. 



Meanwhile it has always been clear that 

 within certain limits the existence of these 

 equilibria is essential to the preservation of 

 life itself, and that they might have been 

 taken for granted. The real question has 

 been to define the normal and pathological 

 fluctuations, their duration, their limits 

 and their relations to other phenomena. In 

 short, so far as these problems are con- 

 cerned, the study of metabolism has con- 

 sisted in an attempt to describe as thor- 

 oughly as may be, and if possible to explain, 

 the fluctuations of the approximately con- 

 stant physical and chemical conditions of 

 the body. In other words, the task of the 

 investigator has been to make known the 

 facts concerning the regulation of the ulti- 

 mate physical and chemical constitution of 



