INTRODUCTION 



A biologist is one whose subject of work is, or has been, 

 living matter. The subject Biology, however, like a 

 polyhedron, has numerous faces, each one more or less 

 circumscribed and independent of the others. Each has 

 its group of followers and its particular name and may be 

 looked upon as an independent science, but this inde- 

 pendence is quite superficial, for at bottom all are correlated 

 and no one of them is more entitled to the name Biology 

 than any other. It is customary in practice, to divide 

 the biological sciences into two groups of equal value; the 

 one Zoology, dealing with animal life, past and present; 

 the other, Botany, dealing with plant life. They may 

 also be divided into two unequal groups, Morphology and 

 Physiology, the former dealing, descriptively for the most 

 part, with the structures of animals and plants, the latter 

 dealing, experimentally for the most part, with the functions 

 or vital activities of animals and plants. This latter 

 division, however, is quite artificial and has little of real 

 value. 



We may enumerate and correlate the biological sciences 

 in some such manner as shown in the accompanying 

 diagram (Fig. i). 



All of the biological sciences enumerated here may 

 have as the subject matter either animals or plants. Thus 

 there is a plant and animal physiology, plant and animal 

 anatomy or morphology, etc. Furthermore, in addition 

 to the main sciences there are numerous subsidiary branches 

 which deal with special groups, such for example as Bac- 

 teriology, Algology, Entomology, Protozoology, etc., most 

 of which are specialized subdivisions of one or more of the 

 sciences given above. Of these, Anatomy deals with the 



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