THE RELATIONS OF PHYSIOLOGY 405 



the side of mysticism. Certain investigators have felt that it was 

 necessary to consider in scientific questions the tendency of the 

 times, which in art and literature was toward mysticism. An 

 attempt has even been made to revive the old doctrine of "life- 

 power." This movement has ended in speculation and fantasy 

 in the problem of development, which is not yet ready for experi- 

 mental investigation. Among physiologists, whose daily expe- 

 rience brings immediately before their eyes the truthfulness of 

 the mechanical conception, the mystical views have found no ad- 

 herents. But especially in semi-scientific circles such words as 

 "Vitalism" and " Neovitalism " have been considered the most 

 modern in science and spread abroad with more energy than under- 

 standing. In opposition, the standpoint of scientific physiology 

 is, to-day, completely clear. 



In reality the matter is quite simple. The subject of investiga- 

 tion of physiologic experiment is the living organism. As natural- 

 ists, physiologists can only have the task of analyzing scientifically 

 the phenomena of the living body. Only that which is percep- 

 tible is, however, accessible to scientific analysis, and nothing but 

 perceptible objects can ever be the subject of scientific investiga- 

 tions. The general principles and laws of phenomena in the per- 

 ceptible world are studied by physics and chemistry, and both 

 have carried their knowledge to a high degree. The organism, as 

 a perceptible object, must be subject to the general laws which 

 rule the perceptible world, and, therefore, we cannot analyze the 

 life-phenomena of organisms otherwise than according to the prin- 

 ciples of physics and chemistry. Physiology is, in other words, the 

 special physics and chemistry of organisms. As organisms are 

 composed of the same elements which are found in the inorganic 

 world, no other factors can apply than those which are seen in the 

 inorganic world, and the special peculiarities of the organism can 

 only be based upon the specific combination of physical and chem- 

 ical phenomena, for physiologic analysis must finally go back to 

 general principles, as only then is its task fulfilled. For mystic 

 factors, not of a physical or chemical nature, there is no place in 

 physiology; as they would not be comprehensible by human know- 

 ledge if they were not perceptible or with perceptible effects, and 

 therefore would always remain hypothetical. 



This standpoint has always given practical results. Everything 

 which has ever been fixed by physiologic investigation has arisen 

 from the practical application of this conception of physiology, 

 as the physics and chemistry of the organism. "Life-power" has 

 not made the slightest addition to the explanation of life-phenom- 

 ena, in the entire development of physiology. 



From the conception of physiology as the special physics and 



