PHYSIOLOGICAL RESEARCH AND REASONING. 153 



range of the observer ; the latter implies the use of apparatus, 

 and is more complex, more extended, more delicate, and precise. 

 It is usually employed with the graphic method, which has the 

 advantage of recording and thus preserving movements which 

 correspond with more or less exactness to the movements of 

 tissues or organs. It is valuable, but liable to errors in record- 

 ing and in interpretation. 



The logic of physiology is that of the inductive sciences. It 

 proceeds from the special to the general. The conclusions of 

 physiology never pass beyond extreme probability, which, in 

 some cases, is practically equal to certainty. It is especially 

 important not to make generalizations that are too wide. 



