Z HUMAN PHYSIOLOGY. 



This may naturally be divided into : 



1. Special physiology, the object of which is a study of the vital phe- 

 nomena or functions exhibited by the organs of any individual 

 animal. 



2. Comparative physiology, the object of which is a comparison of the 

 vital phenomena or functions exhibited by the organs of two or 

 more animals, with a view to unfolding their points of resemblance 

 or dissimilarity. 



Human physiology is that department of physiologic science which 

 has for its object the study of the functions of the organs of the 

 human body in a state of health. 



Inasmuch as the study of function, or physiology, is associated with 

 and dependent on a knowledge of structure, or anatomy, it is essential 

 that the student should have a general acquaintance not only with the 

 structure of man, but with that of typical forms of lower animal 

 life as well. 



If the body of any animal be dissected, it will be found to be com- 

 posed of a number of well-defined structures, such as heart, lungs, 

 stomach, brain, eye, etc., to which the term organ was originally 

 applied, for the reason that they were supposed to be instruments 

 capable of performing some important act or function in the general 

 activities of the body. Though the term organ is usually employed 

 to designate the larger and more familiar structures just mentioned, 

 it is equally applicable to a large number of other structures which, 

 though possibly less obvious, are equally important in maintaining 

 the life of the individual e. g., bones, muscles, nerves, skin, teeth, 

 glands, blood-vessels, etc. Indeed, any complexly organized structure 

 capable of performing some function may be described as an organ. 

 A description of the various organs which make up the body of an 

 animal, their external form, their internal arrangement, their rela- 

 tions to one another, constitutes the science of ANIMAL ANATOMY. 



This may naturally be divided into : 



1. Special anatomy, the object of which is the investigation of the 

 construction, form, and arrangement of the organs of any indi- 

 vidual animal. 



2. Comparative anatomy, the object of which is a comparison of the 

 organs of two or more animals, with a view to determining their 

 points of resemblance or dissimilarity. 



