156 VARIOLA EQUINA — HORSE POX. 



the joints, or from any untoward circumstances, tliese do not 

 heal by the natural cicatrization, the purulent discharge is 

 very apt to become excessive, and the healing is delayed being 

 accomplished by granulation beneath a scab formed by the 

 desiccated discharge. During the continuance of the eruption, 

 and even after perfect desiccation, there is usually considerable 

 swelling of the limbs, and even of the inferior surface of the 

 body — this swelling remaining persistent for weeks after the 

 animal is otherwise perfectly restored to health. 



When the eruption of equine variola is situated in the mem- 

 brane of the mouth, it is somewhat diiferent from that which 

 is situated on the cutaneous surface of the body. Tenderness 

 and pain are indicated by the difficulty or inability to masti- 

 cate and swallow, and by the ejection of fluids from the 

 nostrils. Ropy saliva is abundant in, and dribbling from, the 

 mouth. 



On examination the mouth exhibits vesicles of somewhat 

 varying character and stage of development, scattered singly 

 or collected in groups over the buccal membrane, covering the 

 cheeks and along the sides of the tongue. When occurring on 

 the membrane of the mouth and lips, as also over the margin 

 of the nasal openings, these vesicles are smaller than such as 

 are encountered on the limbs ; they, however, pass through 

 similar regular stages of development, and usually heal more 

 kindly. 



The entire course of equine variola may be regarded as 

 rather rapid, and not prolonged, but perfectly benign. The 

 entire period of its duration, from the reception of the infect- 

 ing material to the occurrence of the desquamative process, is 

 rarely over three weeks : of this period the most important is 

 that occupied by the eruptive stage, or the time during Avliich 

 the diagnostic lesions are most readily distinguished — this may 

 be said to be eight days ; the period taken up by the fever 

 prior to the appearance of the eruption is only a few days. 

 Although the last stage, or that of desquamation, is generally 

 completed in twenty days from the appearance of the invasion 

 fever, the complete restoration to health is often retarded by 

 the appearance of a secondary eruption, or by complications 

 connected with the results of the localization of the virus in 

 the skin and subcutaneous tissues. The pustules, from being 



