BUREAU OF ANIMAL INDUSTRY. 



221 



most severe cases the line of constriction formed at the upper third of 

 the metatarsal bone and the fleshy parts sloughed off, leaving the un- 

 covered bone protruding for more than half its length. Plates V and 

 VI are drawings made from limbs which I secured in Kansas. 



It was reported by some of the veterinarians that small vesicles were 

 formed in the interdigital space and about the coronet, and this was 

 doubtless true, as such vesicles are not uncommon in gangrene ; but 

 their appearance was far from being the rule, as 1 did not succeed in 

 finding a single one in all the animals that I examined. In nearly all 

 of the cases, whether the foot was affected with dry gangrene or whether 

 there had been simply lameness without death of the part, the skin of 

 the interdigital space and about the coronet was perfectly preserved. 

 There was loss of neither epidermis nor hair, as there certainly would 

 have been had the disease commenced by a superficial inflammation in 

 this region and extended to deeper parts of the foot or to higher parts 

 of the limb. Indeed there were no abscesses, no burrowing of pus, no 

 ulceration about the feet, which could lead one for a moment to sup- 

 pose that the cause of the disease had commenced its action externally 

 and extended gradually to the interior of the limb. On the other hand, 

 the fact that the skin was intact in the great majority of cases, that the 

 part was cold and insensible almost from the first, and that the line of 

 separation passed entirely through the limb, removing one or more 

 phalanges as completely as it could have been done with a knife, was 

 sufficient evidence that the disease had an internal origin. 



The gangrene was not confined to the feet, however, for in Kansas, 

 Missouri, and Illinois there were individual animals which were losiug 

 from 2 to 6 inches of the lower part of the tail by exactly the same 

 process. The portion below the dividing line was very dry and hard, 

 while the line itself was sharply defined, as though it had been a knife- 

 cut. With the greater part of the animals affected in the feet a careful 

 examination of the end of the tail revealed a slough of greater or less 

 extent ; sometimes it was simply the skin at the tip that was affected, 

 but oftener one-half inch, 1 inch or 2 inches would be found discolored, 

 lifeless, and dry. In a very few cases a part of the ear was found in 

 the same condition. 



One of the most interesting features of the enzootic, because it had 

 not been heretofore described, was the implication of the mucous mem- 

 brane of the mouth. With some animals this was limited to a more or 

 less diffuse red discoloration, without loss of substance. More fre- 

 quently there were circumscribed dark red spots or patches, from a 

 fourth of an inch to an inch in diameter. Very often there was loss of 

 substance — erosions from a third to a half inch in diameter. Some of 

 the veterinarians reported that they had discovered blisters in the 

 mouths, and it is not unlikely that these erosions in their first stages 

 were more or less vesicular in character, but I was not fortunate enough 

 to see them in this stage at any of the places visited. In some animals 

 the part of the membrane that was being lost was still attached by 

 shreds, in others it was entirely removed, but in no case did I see any- 

 thing of the nature of a vesicle. None of the erosions presented the 

 appearance of ulcers, or showed any considerable inflammation. They 

 were dark-colored, the borders were not elevated, and the surrounding 

 blood-vessels were neither prominent nor injected. It appeared to be 

 only the superficial layer of the membrane that was involved. 



In a very few animals a lesion of a different character was observed 

 in the mouth. In these cases an irregular patch of mucous membrane 

 from 1 to 2 inches in diameter was elevated, corrugated upon its surface, 



