INTRODUCTION. 



As a laboratory exercise the anatomical study of an animal is 

 chiefly a matter of applying a certain practical method of exposi- 

 tion, the student's attention being concentrated on those facts 

 which can be made out by direct observation. This method is 

 educative in the technical sense because it involves accurate 

 discernment of detail, and, as a means of obtaining first-hand 

 information, it is the foundation of laboratory practice. 



In studying the structure of any organism, however, it is to be 

 considered that the final object is not simply to determine in what 

 its structure consists, i.e., its anatomy in a restricted sense, but 

 also to understand what structure signifies, either as functional 

 mechanism, or as the product of racial or evolutionary factors. 

 While it is conceivable that a single organism, either as individual 

 or .species, may be considered by itself, a very superficial study 

 suffices to show that the structure and function of no living organism 

 can be interpreted apart from the general arrangements of organized 

 nature, and more especially frora the corresponding features of 

 those organisms most nearly allied in point of resemblance. 



This being the case, it becomes a more or less practical question 

 in comparative study combined with dissection, or other forrn of 

 laboratory practice, what the proper procedure should be. So far 

 as the present book is concerned, it is expected that the study of the 

 type will begin with the examination of the prepared skeleton 

 (part II). This will be followed by dissection (part III), in which 

 the order by sections will be found to be of less importance than 

 that of details in any particular region. The general matter of 

 part I is purely accessory, and though necessarily incomplete in 

 many ways, is designed to afford a comprehensive view of the 

 various factors upon which mammalian structure depends. 



Regional sections of the foetus as figured in part. I, or frozen 

 sections of the adult animal, are a useful adjunct, since they can 

 be used either for points of general organization, or, being sub- 

 stantially correct for two dimensions, can be used to remove some 

 erroneous impressions of the position of organs incidental to their 

 displacement in dissection. 



