28 FATHERS OF BIOLOGY. 



The first book opens with a division of the body into 

 similar and dissimilar parts. Besides thus differing in 

 their parts, animals also differ in their mode of life, their 

 actions and dispositions. Thus some are aquatic, others 

 terrestrial ; of the former, some breathe water, others air, 

 and some neither. Of aquatic animals, some inhabit 

 the sea, and others rivers, lakes, or marshes. Again, 

 some animals are locomotive, and others are stationary. 

 Some follow a leader, others act independently. Various 

 differences are in this way pointed out, and there is no 

 lack of illustration and detail, but a suspicion is excited 

 that the generalizations are sometimes based upon in- 

 sufficient facts. The book closes with a description of 

 the different parts of the human body, both internal and 

 external. In speaking of the ear, Aristotle seems to 

 have been aware of what we now call the Eustachian 

 tube, for he says, " There is no passage from the ear into 

 the brain, but there is to the roof of the mouth." ! 



In the second book he passes on to describe the 

 organs of animals. The animals are dealt with in groups 

 viviparous and oviparous quadrupeds, fish, serpents, 

 birds, etc. The ape, elephant, chameleon, and some 

 others are especially noticed. 



The third book continues the description of the 

 internal organs. References which are made to a diagram 

 by letters, a, b, c, d, show that the work was originally 

 1 " History of Animals," i. n. 



