98 DIGESTION AND RESORPTION 



I have entered at some length upon these circum- 

 stances, partly because they are of the greatest 

 practical interest, — the digestion seems to proceed 

 in a similar way in the stomach of a dog and of a 

 man — but also in order to show that the differences 

 observed in experiments "in vitro" and "in vivo" 

 are very easily explicable from the different experi- 

 mental conditions and in some cases do not exist. 

 On the other hand, a closer inspection of the ex- 

 perimental data regarding digestion, secretion, and 

 resorption in an animal's body shows a great number 

 of very simple regularities, the existence of which 

 in such "vital" processes, which depend to a very 

 high degree on psychical effects, was deemed im- 

 possible. It is precisely the negation of the possi- 

 bility of applying for the study of vital processes 

 quantitative methods in the same manner as in 

 exact science, which is the chief argument of the 

 vitalists. According to this opinion, forces which 

 are unknown to us from physics and chemistry 

 ought to interfere with the measurements and spoil 

 their value. 



