80 JUDGING CATTLE 



With the exception of the water, the udder is generally 

 considered to produce as the direct product of it^ own 

 action all the constituents of the milk. The casein, the 

 fat and the milk sugar are elaborated in the udder, the 

 only constituent that is thought not to undergo any 

 change is the water in the blood. However, it is from 

 the blood that the milk is made, for the action of the 

 udder is to so change all the constituents that the milk 

 distinctly becomes the peculiar product of the udder. 



To better understand the construction of the udder let 

 us follow the course of the small opening which exists at 

 the end of the teat. This opening at the upper part of 

 the teat swells into a cistern or milk reservoir, where the 

 milk accumulates to a degree between the time of milking. 

 The milk is prevented from passing out of this cistern 

 through the teat by a small muscle (sphincter) which holds 

 the milk in the udder until relaxed by the stimulation of 

 milking. From this cistern a canal extends further into 

 the udder. This branches many times and at the end of 

 each branch there is a cluster (a lobe) of tissue very 

 similar to a bunch of grapes. What is known as the lobe 

 is similar to the bunch, the lobule resembling one grape, 

 and what is known as the alveoli the seeds of the grape. 

 The alveoli are lined with small cells in which the milk is 

 made. These cells produce within themselves the fat pe- 

 culiar to milk and also secrete the water, salts, etc., that 

 enter into the composition of milk. The milk being se- 

 creted in these millions of small cells, which compose the 

 udder, passes into the branches that lead to them, and 

 from these it passes into the main branch and finally 

 reaches the milk cistern, where it accumulates until milk- 

 ing begins. The four quarters which make up the whole 

 udder are each constructed in the way indicated and they 

 act somewhat independently of each other. 



