ZOOLOGICAL SCIENCES 7 



Anatomy and Embryology tell of relationships that are often 

 unsuspected. Paleontology tells the history of these relationships. 

 Ecology and Zoogeography enable one to interpret the past in 

 terms of the present, which is a cardinal principle in Paleontology 

 as in the related science of Geology. Taxonomy is a summary 

 of all the conclusions regarding racial origins, since classification, 

 based on structure, indicates the degree of relationship that 

 exists among various forms of life and thus reveals their evolu- 

 tionary history. 



Definitions Uke those given in the preceding paragraphs are 

 less interesting than many scientific matters -of-f act, but they are 

 desirable for purposes of introduction. An attempt has been made 

 to give greater significance to these definitions by means of the 

 tabulation (p. 3) , which shows how the more important zoological 

 sciences are related to one another and to the broader problems of 

 Zoology. If, after examining the table, the reader understands 

 why each of the sciences Usted in the right-hand column is cited in 

 a particular place, he has mastered the definitions and has secured 

 an outline of zoological science. 



In such a tabulation it is evident that each subdivision of the 

 right-hand column might contain the names of additional sciences. 

 One's understanding of the definitions may be further tested by 

 considering what other sciences might be so hsted. The unity of 

 life is such that every one of these right-hand subdivisions might 

 contain the names of all the other biological sciences and of 

 the principal physical sciences as well. This is a less striking way 

 of saying that if one could know any single field of nature in all its 

 ramifications one would understand the world in its entirety. 

 Consider, for example, what it would mean to know everything 

 one might conceivably know regarding a single animal: how light 

 from the sun and moon is related to its activities; what physical 

 and chemical changes occur within its body; the nature and 

 origin of the material from which its organs are formed; the process 

 of growth; what makes it, perhaps, an object of beauty in the eyes 

 of man; these and similar questions touch the great problems of 

 the material universe on the one hand and those of the human mind 

 on the other. 



The subdivisions of zoological science above enmnerated find 

 parallels in the science of Botany. While it is desirable at the 

 outset to obtain the comprehensive survey of subject matter that 



