460 LIVER. [CHAP, xxxin. 



increasing in size, till it joins the common bile duct, close to its 

 entrance into the duodenum. At its termination it is as large as 

 a crowquill. Its coats are thin and extensible, its internal surface 

 smooth. It frequently happens that the duct belonging to the 

 lower end of the curved portion or lesser pancreas opens separately 

 into the intestine. In the rabbit the pancreatic duct opens by a 

 separate orifice, sixteen or seventeen inches lower down the intes- 

 tine than the bile duct (p. 250). 



It is not difficult to inject the duct, and through it the ultimate 

 secreting structure of the pancreas, with mercury. This may be 

 best done in some of the smaller mammalia, where the glandular 

 tissue is disseminated in lamellated grains between the layers of 

 the mesentery, and where consequently the ramifications of the 

 duct are naturally spread out towards the ultimate acini. The 

 metal easily penetrates to these parts, and appears in the form of 

 clusters of minute globules, having an average diameter of y ^ of 

 an inch. These indicate, with probable truth, the terminal vesicles 

 in which the duct ends, and which are lined with the epithelium, 

 or true secreting tissue, continuous with that of the duct. 



The vesicular terminations lie in the meshes of the capillary 

 network, as is the case with the follicles of the salivary, and other 

 conglomerate glands. 



The secreting cells are more or less spheroidal in form, and vary 

 somewhat in character according to their age. The mature cells 

 are about the pg^o of an inch in diameter, and are opaque, in con- 

 sequence of being filled with numerous minute oil globules. The 

 young cells are smaller than these, and are not so opaque. 



The epithelium in the larger ducts is of the columnar variety. 

 The wall of the duct appears to be composed of fibrous tissue, in 

 which elongated nuclei make their appearance upon the addition 

 of acetic acid. The secretion of the pancreas has been described 

 in chapter xxv. p. 248. 



Liver. The liver is a large solid glandular organ, of firm con- 

 sistence, of a dark reddish brown colour. It measures about twelve 

 inches from side to side, and six or seven inches from its anterior 

 to its posterior border. According to the observations of Krause, 

 the bulk of the liver corresponds to about eighty-eight cubic 

 inches ; its weight is between three and four pounds, and in the 

 adult usually amounts to about l-36th of the weight of the whole 

 body; but in the foetus it is comparatively much larger. The 

 female liver weighs somewhat less than that of the male. The 

 specific gravity of the liver is about 1'05 in health. 



