GANGRENOUS INFLAMMATION OF THE UDDER. 
451 
Abscesses, however, frequently form. Those which occur in the inter¬ 
stitial connective tissue either perforate into the milk canals or through 
the skin. They generally lie deep, and when developing in the con¬ 
nective tissue above the udder (retro-mammary abscess) may lead to 
the destruction of a large section of the gland. Permanent thickening 
and milk fistulae are not infrequent results of this process. 
Hard swellings sometimes result from the accumulation in the milk 
ducts of clots, which gradually become inspissated, and form yellowish 
crumbling masses, surrounded by a capsule of connective tissue. They 
also result from abscesses, and not infrequently form the point of origin 
of disease at a later period. 
Such suppurative processes may entail grave consequences, and at 
times lead to pyaemia or septicaemia. Haase found pulmonary emboli 
in a cow which had died from this disease of the udder. 
Prognosis. There is little hope of completely restoring functional 
activity to the udder during the existing period of lactation. Any 
further opinion must depend on the progress of the disease. When 
large tracts of tissue become indurated, full function will not be 
restored even during the next lactation, and in aggravated cases life 
may even be endangered. For treatment, compare with next section (d). 
(d) gangrenous inflammation of the udder, mastitis gangrenosa. 
Considering the varying virulence of the infectious material, it is not 
surprising that gangrene sometimes occurs. This form of the disease is 
commonest in sheep, though it also occurs in cows and goats, but in the 
latter it does not take the enzootic form generally seen in sheep. 
The nature of the specific poison is at present little understood. 
Nocard isolated from the udder of a sheep suffering from mastitis 
gangrenosa a micrococcus, pure cultures of which, injected into the 
mammary duct of healthy sheep, always reproduced the disease, but 
in other animals only caused slight swelling. 
Symptoms and course. The disease starts as a peracute paren¬ 
chymatous mastitis. Severe general symptons, high fever, loss of 
appetite, great weakness, severe pain, and stiff straddling gait first 
direct attention to the udder. Local examination reveals bluish-violet 
spots on the skin, which on palpation are found to be exceedingly soft, 
insensitive, and often abnormally cool. These spots quickly spread. 
They are surrounded by an inflammatory swelling, which may extend to 
the lower part of the abdomen and the thigh. The animals stand with 
the back arched and the hind legs straddled, exhibit acute pain, groan, 
and after a short time display well-marked symptoms of septicaemia ; 
not infrequently they die within twenty-four hours. 
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