INTRODUCTION. 



AS a laboratory exercise, the anatomical study of an animal is largely a 

 matter of applying a certain practical method of exposition, the 

 student's attention being concentrated on those facts which may 

 be made out by direct observation. For this reason, and also because 

 continuity is a prime consideration, various important aspects of 

 structure are of necessity left in the background. It is to be con- 

 sidered, namely, that in studying the structure of any organism, the 

 final object is not simply to determine in what its structure consists, 

 that is, its anatomy in a restricted sense, but also to understand what 

 the latter signifies when considered either as functional mechanism or, in 

 general, as a product of the various factors underlying it. Every organism 

 reflects in its structure the operation of a variety of influences, and 

 consequently one cannot form an adequate conception of animal or- 

 ganization without considering it from various points of view. In 

 many respects, as indicated below, the interpretation of structure is 

 not simply a matter of what is to be found in a given form, but also of 

 what the latter represents in comparison with others. Assuming, as 

 in the present case, that the student is principally occupied with the 

 routine of a type dissection, the question of how far he may go afield 

 in the consideration of accessory facts is one which must be determined 

 by his own inclinations. His first need, one which the present book 

 endeavours to fill, is to understand the sources of information. Part 

 I, therefore, the subject matter of which has been selected especially 

 with reference to the student who has had no previous experience in 

 the biological sciences, is designed to indicate some of the possibilities 

 in this connection, and also to serve in other ways as an adjunct to the 

 practical account of the structure of the rabbit as outlined in Parts II 

 and III. With the introduction obtained in this way by using the 

 rabbit as an object lesson the student should be able to extend his informa- 

 tion independently, using for this purpose special textbooks in the 

 respective subjects. 



