The Milk Glands and their Functions. 77 



converge to the center of the gland where they form 

 cavities known as the milk sinuses, they used to be 

 termed lactiferous (milk-making) sinuses. 



The milk sinuses empty the lacteal secretion into the 

 teats, each of which is guarded by a sphincter muscle at 

 its lower end, it is this sphincter muscle which is so hard 

 to relax in some cows, that causes them to be termed 

 hard milkers. The udder is lined with a delicate cell 

 structure known as epithelium, this cell structure extend- 

 ing to the alveoli (lobules). 



Shape of Milk Gland. It has been stated that the in- 

 ternal parts of the udder consist of cells and other struct- 

 ures; and as such, require the use of the microscope more 

 or less in their examination, besides the cells, consider- 

 able connective tissue enters into the udder formation, 

 the amount of such tissue materially affects the elasticity 

 of the udder, as it does in muscle. The so-called meati- 

 ness depends on the presence of a large quantity of con- 

 nective tissue, the presence of which cannot help but 

 supplant gland tissue (secreting tissue), therefore we 

 can understand why expert udder-judges want elastic 

 udders on their cows. Prof. Plumb has made a series of 

 studies of the external form of the udder and the rela- 

 tion of that form to usefulness. We cannot do better 

 than note what he says regarding the matter: " A good 

 type of udder will have its side-line, that of the curve of 

 a circle, if a fine udder, it will be carried along beyond 

 the lines of the circle, by an extension along the belly 

 and up between the hind legs, such an udder with teats 

 about three and one-half inches long, make a good type 

 as viewed from the side. Examined from the rear, there 



