Infective Ulcerative Vtdvitis. 653 



the labia, near the border of the inferior commissure, gradually 

 eating its way through until it appeared as a much larger denuded 

 surface on the outside" (C. Miller). S. T. Miller says: "The 

 first noticeable symptom was serous exudate, rapidly forming into 

 a brown scab, under which was very foetid pus, with extensive 

 inflammation. The affection usually occurred on the lower portion 

 of the lips of the vulva, in heifers and cows, and in steers around 

 the anus or root of the tail. The scabs which formed seemed to 

 spread very rapidly, destroying more and more of the underlying 

 tissue and forming a thicker and thicker scab. The scab, if 

 pulled off, would expose a raw surface which would bleed very 

 readily. In a short time a new scab would be formed." 



Steddom says : " The vulvar lips thickened and continued to 

 discharge for four or five days. In the meantime certain pustules 

 appeared, 0.1 to 2.5 centimeters in diameter. About the fifth day 

 these ruptured and discharged yellowish pus." The mucous 

 membranes of the vulva and vagina were dry and slightly con- 

 gested. The ulcers were covered with brown leathery scabs, 

 which adhered tenaciously and when detached left an angry, red, 

 purulent, granular, elevated and pitted surface. In some of the 

 more severe cases, one or both lips of the vulva had sloughed off, 

 and the sore had extended 10 to 15 centimeters on the skin of the 

 escutcheon. The pus from this sore did not corrode the adjacent 

 skin. 



The more severe cases showed loss of appetite, constipation, 

 hurried breathing, tucking up of the abdomen, with general dul- 

 ness and dejection, and great tenderness of the affected skin with 

 stiff, straddling gait. 



Pathology . This is very obscure. The primary cause of the 

 sores is not evident, though their occurrence on the anus and 

 vulva only, and especially on the latter would suggest an elective 

 affinity of the poison (microbian or chemical) for these structures 

 and their products. If we assume a pathogenic microbe in the 

 fasces, the question arises as to the cause of the habitual immunity 

 of the steer, and of the margin of the anus in the majority of the 

 affected heifers. The susceptibility of heifers rather than cows 

 may imply a previous exposure and acquired immunity on the 

 oart of the mature animal. 



