38 ii. 8. 



the other senses it was impossible for nature to unite the medium 

 with the sense-organ, nor would such a junction have served- 

 any purpose ; but in the case of touch she was compelled by- 

 necessity to do so. For of all the sense-organs that of touch 

 is the only one that has a corporeal medium, or at any rate 

 its medium is more corporeal than any other. 



Regarding then the flesh in its sensory character, it is plain 

 that all the other parts exist on its account. By the other parts 

 I mean the bones, the skin, the sinews, and the blood-vessels, 

 and, again, the hair and the various kinds of nails, and anything 

 else there may be of a like character. Thus the bones are a 

 contrivance to give security to the soft parts, to which purpose 

 they are adapted by their hardness ; and in animals that have 

 no bones the same office is fulfilled by some analogous substance, 

 as by cartilage in some fishes, and by fish-spine in others. 



Now in some animals this supporting substance is situated 

 within the body, while in some of the bloodless species it is 

 placed on the outside. The latter is the case in all the Crustacea,^ 

 as the Carcini and the Carabi ; it is the case also in the Testacea, 

 as for instance in the several species known by the general 

 name of oysters. For in all these animals the fleshy substance 

 is within, and the earthy matter, which holds the soft parts 

 together and keeps them from injury, is on the outside. For 

 the shell not only enables the soft parts to hold together, but 

 also, as the animal is bloodless and so has but little natural 

 warmth, surrounds it, as a chaufferette does the embers, and keeps 

 in the smouldering heat. Similar to this seems to be the arrange- 

 ment in another and distinct genus of animal, namely in the 

 Tortoises, including the Chelone and the several kinds of Emys.* 

 But in Insects and in Cephalopods the plan is entirely different, 

 there being moreover a contrast between these two themselves. 

 For in neither of these does there appear to be any bony or 

 earthy part, worthy of notice, distinctly separated from the rest 

 of the body. Thus in the Cephalopods the mass of the body 

 consists of a soft flesh-like substance, or rather of a substance 

 which is intermediate to flesh and sinew, and not so readily destruc- 

 tible as actual flesh. I call this substance intermediate to flesh 

 and sinew, because it is soft like the former, while it admits of 

 stretching like the latter.^ Its cleavage however is such that 

 it splits not longitudinally, like sinew, but into circular segments, 

 664 a. 



