ZOOLOGY 



CHAPTER I 



THE SCOPE OF ZOOLOGY. 



THE word zoology is derived from the Greek word zoon, which 

 meant "animal," and from the termination -logia, which 

 signified a discourse. The name therefore, as might be ex- 

 pected, denotes the science of animals, and is therefore 

 narrower in its scope than the science of biology, which deals 

 with everything living and of which the science of zoology 

 forms a subdivision. 



We see, therefore, that at the outset we are faced with two 

 fundamental questions, viz. (1) What is life ? and (2) What 

 is an animal ? To no two questions is it more difficult 

 to give a precise answer than to these. If with Herbert 

 Spencer we define life "as the continuous adjustment of 

 internal to external relations, " who is the wiser, or who has 

 any better conception of life as a result of the definition ? 



The better way of approaching the problem is the histori- 

 cal one, and instead of asking "What is life V' or "What is 

 an animal ] " let us rather ask how the ideas embodied in 

 the terms " life " and " animal " took their origin. 



The word "animal" is derived from the same root as the 

 Latin word " anima." This originally denoted simply " wind " 

 or " breeze." It was then used to denote " breath/' i.e. the 

 air sucked into and ejected from the lungs in respiration. 

 Breath was recognised by the ancients as the universal 

 concomitant of life and activity in man and animals, and 

 indeed it was regarded by them as the essential principle 

 or cause of animal life. So the word animal signified in the 



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