ARISTOTLE'S HOMCEOMERIA. 115 



formed after the blood has been drawn from the body, 

 and that this fibrin has a tendency to form meshworks in 

 which rolls of red blood corpuscles, like rolls of coins, are 

 entangled, and that the fibrin and corpuscles form the chief 

 part of the blood clot, are facts which were not ascertained 

 until many centuries after Aristotle's time. 



The blood of oxen, Aristotle says, coagulates more quickly 

 than that of other animals, and the blood of the deer, roe, and 

 Bouhalis, probably the Bubaline Antelope, does not coagu- 

 late.* In another passage, in il. ^. iii. c. 6, a somewhat 

 different statement is made, for he says that " fibres " do not 

 occur in the blood of the deer, roe, and Bouhalis, and the 

 blood of these animals does not coagulate like that of other 

 animals, but the blood of the deer coagulates like that of 

 hares, the clot not being firm, while the blood of the 

 Bouhalis coagulates to a greater degree, for it thickens 

 almost as much as that of sheep. 



According to Thackrah's experiments, the blood of the 

 ox does not coagulate more quickly than that of other 

 animals. These experiments showed that the blood of the 

 ox begins to coagulate in from two to ten minutes, that of 

 the sheep, pig, or rabbit in from one ^to two minutes, and 

 that of the horse in from five to thirteen minutes, f 



Fibrin is formed in the blood of the deer, roe, antelope, 

 and most other, if not all, mammals, but it is not normally 

 present in the living body. Aristotle thought that the blood 

 of the deer, the one specially referred to being the red 

 deer (£\a(po(), and that of the Bouhalis coagulate, but that 

 the clot was soft. When describing various causes which 

 prevent blood from coagulating, John Hunter says : " Two 

 deer were hunted to death .... On opening them, the 

 blood was fluid, only a little thickened, and the muscles 

 were not rigid." | It is known that the blood of hunted 

 animals coagulates, but only imperfectly, and, as the animals 

 mentioned by Aristotle are such as are commonly hunted, it 

 is probable that he is referring to the imperfect coagulation 

 of the blood of animals hunted to death. The blood of deer 

 which have not been hunted to death coagulates in the 

 usual way, a fact clearly stated by Redi.§ 



" H. A. iii. c. 6, iii. c. 14, s. 2 ; P. A. ii. c. 4, 651(i. 

 f Op. cit. p. 154. 



I The Works of John Hunter, edited by James F. Palmer, 1835-37, 

 vol. i. p. 239. 



§ Exper. circa res Divers. Natural. 1675, p. 160. 



