INTRODUCTION. 31 



methods, which seek to discover the properties and functional relationships of 

 the tissues and organs by the use of direct experiments. These experiments 

 may be of a surgical character, involving the extirpation or destruction or 

 alteration of known parts by operations upon the living animal, or they 

 may consist in the application of the accepted methods of physics and 

 chemistry to the living organism. The physical methods include the study of 

 the physical properties of living matter and the interpretation of its activity 

 in terms of known physical laws, and also the use of various kinds of physical 

 apparatus such as manometers, galvanometers, etc. for recording with accuracy 

 the phenomena exhibited by living tissues. The chemical methods imply the 

 application of the synthetic and analytic operations of chemistry to the study of 

 the composition and structure of living matter and the products of its activity. 

 The study of the subjective phenomena of conscious life in fact, the whole 

 question of the psychic aspects or properties of living matter for reasons 

 which have been mentioned is not usually included in the science of physiol- 

 ogy, although strictly speaking it forms an integral part of the subject. This 

 province of physiology has, however, been organized into a separate science, 

 psychology, although the boundary line between psychology as it exists at 

 present and the scientific physiology of the nervous system cannot always be 

 sharply drawn. 



It follows clearly enough from what has been said of the methods used in 

 animal physiology that even an elementary acquaintance with the subject as a 

 science requires some knowledge of general histology and anatomy, human as 

 well as comparative, of physics, and of chemistry. When this preliminary 

 training is lacking, physiology cannot be taught as a science ; it becomes 

 simply a heterogeneous mass of facts, and fails to accomplish its function as a 

 preparation for the scientific study of medicine. The mere facts of physiology 

 are valuable, indeed indispensable, as a basis for the study of the succeeding 

 branches of the medical curriculum, but in addition the subject, properly 

 taught, should impart a scientific discipline and an acquaintance with the 

 possible methods of experimental medicine ; for among the so-called scientific 

 branches of medicine physiology is the most developed and the most exact, 

 and serves as a type, so far as methods are concerned, to which the others 

 must conform. 



