PREFACE. 



Experimental physiology is now recognized as a fundamental 

 subject in the curriculum of the medical student and as one having 

 a most important place in the training of the student of biology. 

 In the medical course, the physiological laboratory serves as the 

 portal to the clinic; as the testing ground where the student may 

 try for himself in how far the known laws of physics and chemistry 

 can be successfully employed to explain the normal working of the 

 human machine. No more can theoretical study, or demonstra- 

 tion, by itself supply a correct understanding of the functions s pf 

 the living body than could similar methods in training an engineer 

 to understand an engine. Attempts to rectify, by operations or 

 by drugs, functional derangement in the diseased animal without 

 a practical knowledge of the normal working of the various organs, 

 both isolated and as a whole must be as unjustifiable as attempting 

 to repair a complicated piece of machinery would be by any other 

 than a practical engineer. 



In the training of the biologist, experimental physiology finds 

 its value because it teaches how to interpret the relationship be- 

 tween structure and function. For the advancement of physio- 

 logical knowledge it is essential that the functions of the lower 

 animals should be more intensively investigated by those who 

 have been trained in the methods of the experimental physiologist. 

 In the crowded curriculum, either of medicine or of biology, it 

 is impossible to find an amount of time that is sufficient for the 

 performance of more than a few of the fundamental experiments 

 in each of the main subdivisions of the subject of physiology. 

 It is the duty of the teacher, therefore, to select these experiments 

 with the greatest care so that the experience which the student 

 gains in their performance may guide him aright in building up 

 his knowledge of this subject. The experience gained in the labora- 

 tory is to serve as the framework upon which the detailed con- 

 struction is to be completed by fitting on to it in their proper re- 

 lationship to one another the other facts of physiological know- 

 ledge, acquired by theoretical study and demonstration. 



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