Vesicular Exanthema of Horses. 363 



or pustules. When transferred to man or ox it develops an 

 eruption which is indistinguishable from cowpox (Trasbot, 

 Peuch, Galtier). Still a first attack does not always confer im- 

 munity, as stallions may have two successive attacks within a 

 few weeks (Steinhoff). This implies that either this is not gen- 

 uine cowpox, as claimed in France, or that two different exan- 

 thematous affections have been classed as one. Inoculation with 

 the virus has produced a characteristic eruption in sheep, goats 

 and pigs. 



Symptoms . After a period of incubation of from one to six 

 days there appear heat, swelling and tenderness of the affected 

 part, followed by the formation of papules, gradually passing 

 into vesicles, pustules and scabs which scale off, leaving a white 

 depigmented surface. In stallions and mares the usual seat of 

 the eruption is the external generative organs ; in young sucking 

 animals the mouth, lips, nose and quarters, and in inoculated 

 cases wherever the virus has been implanted. 



In the mare there is swelling of the lips of the vulva and 

 redness of the vaginal and vulvar mucosa with points of a 

 darker red, which become firm, papular, vesicular and finally 

 pustular. A similar eruption shows on the skin of the swollen 

 labise, on the lower surface of the tail and on the hips, though 

 on these points the phenomena are obscured somewhat by the 

 abundance of pigment. The contents of the vesicles are at first 

 limpid but gradually change to opaque yellowish- white, brown, 

 or even red from slight blood extravasation. It causes not only 

 marked tenderness but great itching so that the patient rubs the tail 

 and rump, rupturing the vesicles, causing blood extravasations 

 and retarding healing. The sores are primarily two or three lines 

 in diameter but may widen and deepen under the friction. The 

 surface may be red and angry and covered hy a yellowish viscid 

 discharge. When they heal they leave on the dark skin, round 

 spots white and devoid of pigment. The itching during the 

 acute stage of the disease, leads to generative excitement, fre- 

 quent straining, contractions of the erector clitoris and ejection 

 of urine. The animal appears to be constantly in heat, yet the 

 absence of hyperthermia shows that there is no constitutional 

 disorder nor central nervous affection. The disease appears to 

 be purely local. 



