OF VETERINARY MEDICINE. 25 



tured a# moisture comes out. If occur ing in white skin the color 

 is black. In the horse the color of the gangrenous part is not 

 so well contrasted. The dead part decomposes rapidly and sul- 

 phuretted hydrogen is produced, which is found in solution in 

 the moisture of the decomposing mass, giving it the odor of 

 rotten eggs, a most characteristic smell. A silver probe inserted 

 in the tissue will at once become black. Between the living 

 and the dead parts there is a red line of demarcation. If the 

 gangrenous portion is small, the part may slough off, the separa- 

 tion taking place at the line of demarcation. By getting rid of 

 the dead part the life of the animal is saved; but if the dead 

 portion is too large to remove, absorption of the putrefactive 

 matters takes place and poisons the blood and kills the animal. 

 The dead part is usually spoken of as having a cadaverous smell. 



In the time of the outbreak of contagious pleuro-pneumonia 

 in 1887, the disease was found to have existed for two years 

 among the cows in the distillery sheds fed on distillery slops. 

 Amongst these cows were many with bob-tails and it was said 

 that the bull-dogs had bitten them off. But upon inquiry it was 

 found that these animals had been inoculated against pleuro- 

 pneumonia, and that a careless method of inoculation (serum 

 probably decomposed) had set up a violent inflammation in their 

 tails. These had become gangrenous and had sloughed off. 



Moist gangrene often occurs in the lower lobe of the lung. 

 The part cannot slough off and the animal dies from absorption 

 of putrefactive products. 



If moist gangrene occurs in a small part it is called necrosis. 



In fistulous withers we speak of the dead parts removed as 

 necrotic tissue. 



Dry gangrene is death of tissue when the part dies from 

 inanition, i. e., slowly starving to death. The part becomes 

 paler and paler, losing its natural heat in proportion to the lack 

 of nutrition. 



The results of dry gangrene are: 



1. Mummification — the part dries up, 



shrivels, and dies; it hangs on and 

 will not drop off. 



2. Chalky degeneration (calcareous) — 



