288 Diseases of the Genital Organs 



smooth, moist, and pale rose-colored for a period varying 

 from four to twelve weeks, or even longer. Finally, visual 

 inspection reveals the presence of several or many spheroido- 

 conical nodules in the vulvar mucosa, 1 to 2 mm. in diameter. 

 Usually they are colorless or faintly yellowish in the center 

 and present the appearance of small, tense vesicles, but 

 close examination reveals the fact that they are hard to 

 the touch and contain no fluid. Encircling the base of each 

 nodule, there is usually a pale or bright red area due to in- 

 creased vascularity, giving the lesion the appearance of a 

 minute vesicle, with a vascular girdle. The nodules are 

 scattered here and there, frequently along the floor of the 

 vulva in the clitorial region, but quite as often on the sides 

 or roof of the vulva. Except for the nodules and the vascu- 

 lar girdle about the base of each, the surface of the mucosa 

 in the early stage is smooth, pale rose-colored, and normal. 

 There is no swelling, no inflammation, no discoloration of 

 the vulvar mucosa not occupied by the nodules, and no 

 marked mucous or muco-purulent discharge. 



Slowly and insidiously the disease appears in calves 

 which have hitherto seemed free, so that, the older the 

 heifers, the larger the percentage showing evidences of the 

 infection. The rapidity and uniformity of the development 

 of the malady depend largely upon environment. Usually, 

 in the closely housed heifer calves in large dairies, fed 

 carelessly upon raw, mixed milk, more than 90 per cent, 

 show the disease at four months, and before they are one 

 year old the visible infection reaches 100 per cent. If by 

 any chance an individual escapes infection until breeding 

 age, the first copulation conveys the disease. In heifer 

 calves of the beef breeds, which nurse their dams, the in- 

 fection develops much more slowly. In experimental heifer 

 calves, I have kept individuals up to six months, and even 

 to one year old, without any visible trace of infection. 



The influence of environment upon the spread of the in- 

 fection in heifer calves is further shown in Table I, wherein 

 the 122 veal heifers observed showed an average infection 

 of 61 per cent. The percentage of infection among these 



