108 AEISTOTLE'S HOMGEOMERIA. 



per cent, in excess of those found in the bones of Man and 

 the ox.* Whether the bones of Hons are harder than 

 those of other animals would be very difficult to deter- 

 mine, but many of the bones of other carnivores are very 

 hard, and so also are some of the bones of hares, rabbits, 

 birds, and snakes. 



Aristotle says that cartilage is of the same nature as 

 bone, but differs in degree, and, like bone, does not grow 

 after it has been cut away,t that in viviparous land animals 

 it does not contain marrow in the same way as bones, and 

 that it occurs about the ears, noses, and some extremities of 

 bones in viviparous quadrupeds. I 



It is evident from these passages that he was aware of a 

 close relationship between bone and cartilage, but there is 

 nothing to show that he knew anything about the conver- 

 sion of some cartilages into bone by ossifying processes. 

 When he says that bone and cartilage differ in degree, he 

 means that they manifest different degrees of certain 

 qualities, such as, for example, hardness, strength, and 

 heaviness. 



In his statement about bone or cartilage not growing again, 

 it is evident that he is not referring to a slicing or sever- 

 ance which still leaves the sliced or severed ends in contact ; 

 this is shown by his using the verb aTroxoVrw (I cut or break 

 off) . A precisely similar statement is made twice in one of 

 the genuine works of Hippocrates, the same verb being 

 used.§ In all probability, Aristotle copied, in this instance, 

 from Hippocrates. It is now known that, when a part of a 

 bone or cartilage has been removed, the bone or cartilage is 

 reproduced, provided the periosteum or perichondrium, as 

 the case may be, has been left. Aristotle knew nothing 

 of this, but he was aware of the importance of the 

 periosteum in protecting the substance of the bone, for he 

 says " bones which have been stripped bare of their 

 membranes mortify." || In one of the genuine works of 

 Hippocrates there is a passage which seems to show that 

 mortification sets in when the membrane of a bone has been 

 removed. H 



2. Sineivs, "Fibres," and the like. — Aristotle repeatedly 

 uses the words vsopov and <"? {neuron and is) to denote certain 

 constituents of the body. It is often difficult to determine 



^= Anat. Vertebr. vol. i. 18G6, p. 20. 



t H. A. iii. c. 8 ; P. A. ii. c. 9, Go5a. | H. A. iii. c. 8. 



§ Aphorisms, Section 6, § 19 and Section 7, § '28. 



I| H. A. iii. c. 11, s. 1. *\ On Fractures, § 33. 



