B. Hi.] THE niSTOBT OF ANIMALS. 65 



sting of the bee grow after it is plucked out, but the animal 

 dies. 



CHAPTER XI. 



1. THERE are membranes in all sanguineous animals. Mem 

 brane is like a dense thin skin, but it differs m kind, for it 

 is neither divisible nor extensible. There is a membrane 

 round every bone and every intestine, both in the greater 

 and smaller animals ; they are inconspicuous in small ani 

 mals, owing to their thinness and small size. The principal 

 membranes are two, which surround the brain, one round 

 the bones of the head, and this is stronger and thicker than 

 that round the brain itself; and after these, the membrane 

 which surrounds the heart. A thin membrane does not 

 unite after it has been cut asunder, and the bones, when de 

 prived of their membranes, become inflamed. 



2. The omentum is a membrane. All sanguineous ani 

 mals have an omentum ; in some it is fat, in others it con 

 tains no lilt. In viviparous animals, with cutting teeth in 

 both jaws, it has its origin and is suspended from the middle 

 of the stomach, where it appears like a suture of this organ. 

 In those that have not teeth in both jaws, it is suspended 

 in the same way from the principal stomach. 



3. The bladder also is membranous, but its character is 

 different, for it is extensible. All animals have not a 

 bladder, but all viviparous animals have this organ, and the 

 tortoise alone of oviparous animals. When the bladder is 

 cut it does not re-unite, except at the very origin of the 

 urethra, or only very rarely, fur it has happened sometimes. 

 No moisture passes into the bladder of dead animals ; but 

 in living creatures there are dry compounds, from which are 

 formed the stones that are found in persons labouring under 

 this disease ; sometimes they are of such a nature in the 

 bladder as to differ in nothing from shells. This, then, is 

 the nature of veins, sinews, and skins, and of muscle and 

 membrane ; and of hair, nails, claws, hoofs, horns, teeth and 

 beaks, and of cartilage, bone, and their analogues. 



CHAPTER XII. 



1. IN aH sanguineous animals, flesh, and vuat which is like 

 flesh, is between the skin and the bone, or what is analogous 



