206 TJDDER GLANDS. 



the glands, holding them in position, and, by their 

 elasticity and firmness, acting an important part in an 

 organ subject to such violent changes of size. Fatty 

 tissue occurs near the surface of the glands, and 

 between their interstices, to a greater or less extent ; 

 and in the virgin heifer largely determines the form 

 and size of the bag. 



The teats, usually projecting slightly forward in 

 the heifer, are likewise covered with a skin similar to 

 that of the udder, but uncovered with hair, pliant, 

 flexible, and creased. Their number corresponds to 

 that of the glands, and they are interesting as form- 

 ing the outlet for the secretion, as well as their 

 mechanical adaptation to the needs of the calf. Their 

 structure is an areolar and fibrous tissue beneath the 

 skin, which, by its elasticity, closes the outlet and 

 prevents the escape of the milk. Sebaceous glands 

 are present, particularly at the base, and their 

 secretion renders the surface soft, and less subject 

 to injury. 



The gland portion consists of ducts, reservoirs, 

 glandules, and connective matter. The reservoirs 

 are situated mostly at the periphery and apex of the 

 gland, and more particularly adjacent to the sides 

 covered by the skin of the animal. It is the reser- 

 voirs which cause the tabulated feel of the surface 

 of the udder, in large part, and they serve to enclose 

 the secreting surface, which principally occupies the 

 centre. The glandules or vesicles, in their arrange- 

 ment, form groups, and each group has its duct, 

 which connects with the ducts from other groups, 



