INTRODUCTION 



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

 living matter. The subject Biology, however, like a poly- 

 hedron, has numerous faces, each one more or less circum- 

 scribed 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 independence 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 dia- 

 gram (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 anat- 

 omy 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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