Chap.x.] THE HEART AND BLOOD-VESSELS. 



81 



nervous system, the largest in the marrow of bone. 

 The capillaries form always networks, the richness and 



Fig. 48. From a Preparation of the Peritoneum, stained 

 with Nitrate of Silver. 



a, The endotheltum on the free surface of the membrane ; 6, the capillary blood- 

 vessels in the membrane ; their wall is a layer of endothelium. (Handbook.) 



a 



Fig. 49. Young Fat Tissue of the Omentum, its Blood-vessels injected 

 a, Artery ; 6, vein ; c, network of capillaries. (Handbook.) 



arrangement of which vary in the different organs, 

 according to the nature and arrangement of the ele- 

 ments of the tissue (Fig. 49). 



