PARTS OF ANIMALS, II. vi. 



Some animals have no marrow worth mentioning l 

 these are they whose bones are strong and close- 

 textured : for instance, the Lion, whose bones con- 

 tain so insignificant an amount of marrow that they 

 look as if they contained none at all. Now in view of 

 the fact that the bodies of animals must have in them 

 either bones or the counterpart of bones {e.g. the 

 spines in water-animals), it follows of necessity that 

 some of them must contain marrow as well, due to the 

 enclosing of the nourishment out of which the bones 

 are formed. Now we have stated already that the 

 nourishment of all the parts of the body is blood. 

 And it is quite reasonable that the various sorts of 

 marrow should be suety and lardy ; because the 

 blood undergoes concoction owing to the heat pro- 

 duced by its being surrounded by bone, and the 

 product of blood when it undergoes concoction by 

 itself is suet and lard. And also, of the animals that 

 have strong, close-textured bones, some have no 

 marrow, others have but little, and this is reasonable 

 too, because the nourishment gets used up to supply 

 the substance of the bones themselves. 



In those animals that have no bones but spine 

 instead, the backbone contains the only marrow they 

 possess. It is the nature of these creatures to have 

 but a small amount of blood, and their only hollow 

 spine is that of the backbone. Therefore the marrow 

 is formed in it — indeed, it is the only bone where 

 there is room for the marrow, and the only one 

 which requires something to connect it together, 

 owing to its being divided up into segments. 

 This also explains why the marrow here is (as 

 I have already said) somewhat different from the 

 marrow elsewhere. It has to serve as a fastening, 



147' 



