116 ARISTOTLE'S HOMCEOMERIA. 



Aristotle believed that ferocity and liability to fits of 

 passion were dependent in some way on the quantity of 

 "fibres" in the blood. According to him the "fibres" are 

 earthy and solid, and, acting like the hot embers in a vapour 

 bath, cause ebullition in the blood, this being the reason why 

 oxen and boars are so passionate, for their blood is rich in 

 "fibres."* The animals mentioned in H. A. iii. c. 6, viz., 

 the deer, roe, antelope, hare, and sheep, are usually con- 

 sidered to be timid, and Aristotle evidently thought that 

 they had but few " fibres " in their blood, compared with 

 those in the blood of the ox or boar. 



Thackrah's experiments support Aristotle's view that the 

 ferocity of an animal depends, in some way, on the quantity 

 of " fibres " in the blood. After making numerous experi- 

 ments he concluded thus : "I never found the serum in 

 such quantity as in the timid sheep, nor the crassamentum 

 so abundant as in the predatory dog." t 



9. Milh. — All milk, Aristotle says, consists of a watery 

 fluid, which is called whey, and a thicker part, called curd, 

 the thicker kinds of milk containing more curd than other 

 kinds. X He also says that the milk of the camel is thinnest, 

 then that of the mare, and then that of the ass, but cow's 

 milk is thicker. § There is a fatness in milk, he says, which 

 causes it to become oily when the milk has been coagulated 

 or thickened.il In cows' milk there is more curd, he says, 

 than in goats' milk, for the herdsmen say that they make 

 from about nine gallons of goats' milk nineteen cheeses, each 

 worth an obolos, and thirty from cows' milk.^ 



The above are the chief statements made by Aristotle 

 about the nature and composition of milk. He gives 

 correctly the relative degrees of consistency of the milk of 

 the cow, ass, and mare, but his statement about camel's 

 milk is incorrect. Camel's milk is nearly, if not quite, as 

 thick as cow's milk, and contains a little less water and 

 casein, more sugar, and about as much fat as the latter. 

 The assertion in H. A. iii. c. 16, s. 5, is difficult to under- 

 stand. Average samples of cows' milk and goats' milk 

 contain nearly the same amount of casein, that in goats' 

 milk being, if anything, the larger. The Greeks, it may be 

 mentioned, did not esteem cows' milk for making cheese, 

 goats' milk having been used most by them. 



* P. A. ii. c. 4, 6506 and 651a. \ Op. cit. p. 154. 



X H. A. iii. c. 16, s. 2. § Ibid. 



II Ibid. iii. c. 16, s. 5. «f Ibid. 



