THE PROTOZOAN SUBGROUPS 335 



The stallion retains his full genetic instinct and becomes very amorous 

 when brought in the vicinity of mares. If allowed access to mares in 

 season, service is often impossible, due to the fact that a complete 

 erection of the penis does not occur. The testicles may be involved and 

 tender to pressure, and abscess formation may occur with sloughing. 



"In the mare the first sjmiptoms may be so slight as not to be noticed 

 by the owner. The disease being the result of copulation, begins with 

 swelling and inflammation of the vulva and vagina. The labia are 

 continually everted, exposing the clitoris, which is constantly in a state 

 of erection. There will also be a muco-purulent discharge hke that 

 coming from the penis of the male, which may be slight or profuse in 

 quantity. The mare will switch the tail, appear uneasy, and urinate 

 frequently. Shortly papules and vesicles appear on the external vulva, 

 as well as on the mucosa of the vulva and vagina. These vesicles soon 

 rupture, but before doing so the contents undergo a change from a 

 transparent to a purulent fluid. The rupture of these pustules is the 

 initial stage in the formation of deep, angry ulcers. These ulcers show 

 a tendency to heal rapidly, but invariably leave a cicatrix. On the dark 

 skin of the external vulva the scars will always be white. This de- 

 pigmentation is permanent. 



"Sometimes, especially in the mare, the above-described lesions tend 

 to disappear gradually, and in case the mare is not served again the 

 disease may remain in abeyance for months or a year. The apparent 

 recovery, however, is not permanent, and any excessive work or excite- 

 ment may set up the disease anew. In case an affected mare conceives, 

 she is liable to abort at any time during her term of pregnancy. When 

 the fetus is carried to full term, it occasionally is a weak or imperfectly 

 developed foal, but in this country many fine colts have been born to 

 affected mares. 



"The nervous or constitutional disturbances of the second stage may 

 not come on for months or even a year after the appearance of the local 

 lesions, and are similar in both male and female. They consist of a 

 general nervous disorder with staggering, swaying gait, especially in 

 the hind limbs. The animal becomes extremely emaciated, particularly 

 in the hind quarters, and the abdomen assumes a "tucked-up" appear- 

 ance. The first indication of paralysis will be noted in traveling, when 

 the animal fails to pick up one of the hind feet as freely as the other. 

 There is a tendency to drag the foot partially. This condition may 

 shift from one hind foot to the other, or both may become affected 

 simultaneously. Twitching of the superficial muscles has been noticed 

 in several instances. Urticarial eruptions or plaques may break out 

 over various parts of the body, and there may be noticed pruritus of 

 the skin, which causes the animal to rub itself frequently. The tem- 

 perature of the animal seldom goes above 101° or 102° F. When the 



