SPLEEN VILLI IN THE INTESTINES IN THE HORSE. 119 



and lymphatics being from the same sources whence the 

 adjacent organs are supplied. The peritoneum merely passes 

 over the pancreas without investing it in the form of a com- 

 plete tunic. 



The pancreatic juice is colourless, transparent, and slightly 

 viscid. It has an alkaline reaction, and putrefies rapidly. It 

 has the property, like saliva, of changing starch to sugar. 

 Thence it appears to be concerned in the assimilation of the 

 starchy portions of the food on which the gastric juice has 

 no effect. Some question has arisen on the point how far it 

 is concerned in the assimilation of oily substances. It is 

 certain that the pancreatic juice forms a very perfect emul* 

 sion when agitated with oil, and that this emulsion remains 

 unchanged for many hours. The pancreatic juice contains 

 albumen in the soluble form. 



Spleen or Milt. The spleen is a highly vascular organ, in- 

 vested with a peritoneal tunic varying somewhat in colour, 

 but commonly of a mottled blue or purplish-grey colour. It 

 has been believed that there is a peculiarity in the structure 

 of the spleen in the ox and sheep, in so far that this organ 

 in each " is distinguished by a peculiar cellular structure from 

 the merely vascular texture which it possesses in other ani- 

 mals of this class."* This observation does not, however, ap- 

 pear to have been followed out by recent anatomists. With 

 respect to the general structure of the spleen, the chief par- 

 ticulars known have been already stated in speaking of the 

 spleen of the horse (p. 65). 



Villi of the Intestines. The prominences on the mucous 

 membrane of the primse vise or alimentary passages are, in 

 particular, papilla? and villi. The papilla are small processes 

 of the corium of the mucous membrane, for the most part 

 of a conical or cylindrical figure, enclosing blood-vessels and 



* Blumenbach, by Lawrence, p. 125. 



