B. III.] THE HISTORY OF ANIMALS. 67 



those which have most blood, and in the largest creatures ; but 

 in those animals which are small, and have not much blood, 

 either by nature or from excess in fat, they are not so easily 

 investigated, for some of the passages are confused, like 

 rivulets that are lost in beds of mud ; and there are some 

 animals which have but few, and these fibres instead of veins. 

 The great vein is very conspicuous in all, even the smallest 

 animals. 



CHAPTER V. 



1. THE following is the nature of the sinews of animals. 

 The origin of these, also, is in the breast, for there is a 

 sinew in the principal cavity of the heart itself ; and that 

 which is called the aorta is a sinewy vein, for its termina 

 tions are always sinewy, for they are not hollow, and are 

 extensible, like the sinews which end upon the bending of 

 the bones : for it is not the nature of sinews to be con 

 tinuous from one origin, like the veins, for the veins have 

 the whole form of the body as in outline sketches, so that 

 in emaciated subjects the whole mass appears full of veins, 

 for the same place is occupied by veins in lean persons that 

 in fat ones is flesh. 



2. The sinews are drawn round the joints and flexures of 

 the bones ; but, if their nature were continuous, the con 

 tinuation would be evident in emaciated persons. The 

 principal parts of the sinews are around the part of the 

 body appropriated to leaping, and this is called the poples. 

 Another double sinew is the tendon of the neck, and the epi- 

 toiius and the sinew of the shoulder, which aid in the support 

 of the bodv. The sinews around the joints have not re 

 ceived am name, for all the bones where they are contiguous 

 are bound together by the sinews. 



3. And there are many sinews round all the bones ; there 

 are none in the head; but the sutures of the skull are 

 adapted to each other. It is the nature of sinew to tear 

 readily lengthwise, but across the fibre it is indivisible, 

 and it is very extensible. The sinews are surrounded by 

 a mucous, white, and gelatinous fluid, by which they are 

 nourished, and from which they seem to derive their onni. 

 The vein does not alter its form by combustion, but the 

 einew is entirely destroyed. Neither does it unite alter 

 division. 



