INTRODUCTORY 5 



and its physiology : for the study of the structure 

 of an organ will often suggest the function it fulfils, 

 while the study of function not infrequently aids us 

 in the interpretation of structure. 



There are, however, several other lines of inquiry 

 in reference to organisms that may be followed 

 out with interest and profit. There are, for example, 

 problems connected with the relation of the organism 

 to its environment (Ecology), its occurrence on and Ecology, 

 migrations over the earth's surface (Distribution), 

 and its genealogical relationship to other organisms pistribu- 

 obviously allied to it (Taxonomy), whether these be [j^ l ^ nA 

 now living or represented by more or less perfectly space, 

 preserved remains imbedded as fossils in the earth's onomy. 

 crust. It would be impossible, without greatly 

 increasing the size of the present volume, even to 

 indicate the nature of these problems, let alone discuss 

 them ; nor is it necessary or expedient to do so, 

 seeing that succeeding primers of this series will deal 

 with certain of these questions in greater detail. 

 At present we may confine our attention to the task 

 of endeavouring to obtain some elementary concep- 

 tions of the principles of the science of life, and 

 more especially those on which morphology and 

 physiology are founded, in other words, to gain some 

 idea of the structure of the living machine and of 

 the way in which it works. 



