510 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



the head, as lips, chin, nose, cheeks, gums, and hard palate, are the 

 most frequent, while much less common are the ulcers on the legs 

 and feet. Shear cuts and the tail stump of docked lambs are at times 

 infected, while slit ears have been more frequently involved. In 

 bucks frequently and in wethers occasionally the sheath is infected. 

 The vulva of ewes has been found ulcerated in a relatively small per- 

 centage of cases, while the udder and teats even more rarely have de- 

 veloped the infection, notwithstanding that the sucking lambs showed 

 more or less ulceration and eruptions on the mouth parts. In some 

 cases lesions have appeared in the pharynx and lungs, occasionally 

 in the liver and stomach, and in such instances the disease uniformly 

 results in death. 



It may be advisable to arrange these various manifestations of 

 the disease into the following classes, with the statement that further 

 study is required to explain the reason for necrobacillosis in sheep 

 assuming several different forms or types under what appears to be 

 similar environment, as well as for the disease becoming virulently 

 infective in certain cases, while in others, under practically the same 

 conditions, there is a tendency toward latency or even spontaneous 

 recovery. 



1. The lip-and-leg form, as the name indicates, attacks the lips 

 or legs, or both. The lesions in some bands are confined very largely 

 to the lips and muzzle, in other bands the lesions are largely con- 

 fined to the legs, while in still other bands the seat of the lesions is 

 about equally divided between the lips and legs. 



The different conditions under which the sheep are kept and the 

 character of the feed may account, in a degree at least, for this differ- 

 ence in the seat of the lesions, and also to some extent for the differ- 

 ence in the spread of the disease, especially within the band. Thus, 

 during the winter, when snow is on the ground and the weather is so 

 cold that the surface of the snow becomes hard and crusted, making 

 grazing very difficult, the chances are that leg lesions would be likely 

 to predominate, owing to the numerous scratches received upon the 

 legs becoming infected with the blood and bits of scab which drop 

 from the infected sheep. On the other hand, if they were fed on a 

 range where cactus and greasewood composed a large part of the feed, 

 the spines of these plants would be likely to wound the lips and nose 

 to such an extent that lip lesions would be apt to predominate. Other 

 sheep ranging over such ground after the infected sheep had passed 

 would under such conditions be very likely to contract tne disease. 



This form may assume either the active or the inactive stage. 

 The active stage manifests itself in the various locations by inflam- 

 mation, tumefaction, ulceration, and necrosis, with or without scab 

 formation. There is more or less rapid destruction of the tissue, es- 

 pecially where the lesions are located on the lips or muzzle. Cases 

 are frequently seen where more or less of the lip or the end of the 

 nose has sloughed away as a result of the suppurative inflammation. 



The lesions in the early stage usually appear as an acute inflam- 

 mation of the skin on the outside of the lips. This pimple-like for- 

 mation is attended with much inflammatory swelling, with a decided 



