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2 ( LI BR A ^V 



Introduction 



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

 chiefly a matter of applying a certain practical method of 

 exposition, 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 discern- 

 ment of detail, and because, as a means of obtaining first-hand in- 

 formation, it is the foundation of laboratory practice. Within the 

 range of natural science, which limits fact to what is reasonably 

 demonstrable, laboratory practice takes its place as one of the 

 principal methods by which first-hand knowledge of anything 

 concrete is gained and it is important for the student as early as 

 possible to form the habit of acquiring his knowledge in this way 

 and of confirming thus information obtained otherwise. 



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 as species, may be considered by itself, this provides only a much 

 restricted point of view and a very superficial study suffices to show 

 that the structure and function of no living creature can be ade- 

 quately interpreted apart from the general arrangements of organ- 

 ized nature and, more especially, from the corresponding features 

 of similar or nearly related organisms. 



This being the case, it is a very pertinent question what is the 

 best procedure. So far as the present book is concerned, it is expect- 

 ed that the study of the type will begin with at least a preliminary 

 survey of the prepared skeleton (Part ii). This will be followed by 

 dissection (Part ill), in which the^ order by sections will be found 

 tQ be of less importance than that of details in any particular region 

 and in which portions of the skeleton related to the part under 

 examination may be included. 



The regional method of approach is indicated rather than the 

 more complete study of single systems, partly for the sake of 



