4 Milk and Its Products 
udders are more subject to inflammations and in- 
flammatory diseases than those with less fatty tissue. 
In many cows the fibrous net-work that supports 
the udder is held firmly up to the under side of the 
abdomen. If, in connection with this, the udder has 
comparatively little connective and fatty tissue, the 
animal will have an udder apparently small, but with 
large capacity for secretion. In old cows, particu- 
larly those that have been large milkers, the fibrous 
bands often become largely relaxed, so that the 
udder falls nearly to the ground, and appears to be 
of enormous size. 
Internal structure of the udder and teats. -—- The 
teat is simply a canal surrounded by muscular walls 
and closed at the extremity by an involuntary 
sphincter muscle, which varies much in rigidity in 
different animals; often it is so lax that the pressure 
of a small amount of milk in the canal is sufficient 
to open it and the animal leaks her milk. In other 
animals it requires a strong effort of the hand to 
draw the milk. When desirable, the rigidity may be 
overcome by keeping a smooth wooden plug of suf- 
ficient size to moderately dilate the opening in the 
end of the teat till the muscle relaxes sufficiently 
to permit easy drawing of the milk, or the muscle 
may be partially divided with the knife in the 
hands .of a skilful operator. At the top of the 
teat, or bottom of the udder, there is a small 
cavity known as the milk cistern, serving to hold 
the milk after its secretion until it is drawn. 
It is -of varying capacity, up to half a pint, 
