90 Anatomy and Physiohxjy of the Mammai-y Gland. 



away. Fig. 5 is inserted in order to convey a clear idea of this 

 structure. The lactiferous or excretory ducts are here marked, Oy 



Fi- 5. 



Arrangement of the milk-secreting follicles 

 and lactiferous or excretory ducts : a. an excre- 

 tory duct with its several branches, around wiiich 

 are clustered, b, the secreting follicles or coecal 

 extremities of the ducts. (Magnified.) 



and the milk-secreting follicles, h. From the smaller-sized 

 reservoirs, which are shown both in Figs. 1 and 6, the milk 

 passes through numei'ous canals into tlie large reservoir of the 

 gland, Avhich is situated just above the teat (see Fig. G). Here it 

 is detained inconsiderable quantity, often to the extent of two or 

 more quarts, until drawn off by the sucking of the calf or by the 

 act of milking, which not only empties the large but like- 

 wise all the other reservoirs and milk-ducts. It will thus be 

 seen that by the arrangement of the component parts of the 

 mammap, provision is made not merely for the secretion but for 

 the retention of a large quantity of milk ; the glands of the cow, 

 ewe, and goat differing with regard to the existence of these 

 receptacles, as has been elsewhere stated, from those of other 

 domesticated animals. 



In Fig. 6, which represents the udder of the cow stripped of 

 the skin, its vessels injected, &c., one of the anterior glands is 

 laid open to show the large reservoir, a. The end of a probe is 

 depicted as being passed into it, having been carried upwards 

 tlirough the duct in the teat, b, b, represent the smaller reservoirs, 

 some of which are opening into the large one ; and c, c, shov/ 

 the lobulated condition of the external portion of the posterior 

 glands, which is produced by collections of lactiferous ducts. 



We 



Fig, 6 gives a view of the udder of the cow after being stripped of the 

 skin wliich covers it. The vessels are represented as being filled with 

 injection, and one of the anterior glands has also been cut open, iu 

 (nder to expose the large reservoir in its interior, into which a tube is 

 passed through the passage in the teat : «, the reservoir ; b, smaller 

 reservoirs; c, the outer surface of the posterior glands, whicli have a 

 lobulated condition, produced by bundles of milk-tubes collected 

 together ; d, the mammary veins ; e, the origin of the superficial 

 abdominal vein, commonly called the milk-vein. (Modified from the 

 jilate by Sir A. Cooper.) 



