607 



most frequent carriers of the virus, and we find the lesions in tlie ma- 

 jority of cases developed in the neighborhood of the lips and nostrils. 

 Coition is a frequent cause. A stallion suffering from this disease may 

 be the cause of a considerable epizootic, as he transmits it to a number 

 of brood mares and they in turn return to the farms where they are 

 surrounded by young animals to whom they convey the contagion. 

 Th3 saddle of the harness and croup straps are frequent agents of in- 

 fection. The presence of a wound greatly favors the inoculation of the 

 disease, which is also sometimes carried by surgical instruments or 

 sponges. Trasbot recites a case, in which a set of hobbles, which had 

 been used on an animal suffering from variola, were used on ahorse for 

 a quittor operation and transmitted the disease which developed on the 

 edges of the wound. There is no elective point for the first development 

 of the disease, but it commences most frequently around the natural 

 openings, as these are the points which are most exposed to inoculation. 



Sijmj>to)ns. — There is a period of incubation, after an animal has been 

 exposed, of from five to eight days, during which there is no appreciable 

 alteration in the health. This period is shorter in summer and longer 

 in winter. At the end of this time, small nodes develop at the point of 

 inoculation and the animal becomes feverish. The nodes, which feel 

 like small shot under the skin, soften into small pustules and break 

 into little, shallow, superficial ulcers, exuding a creamy, thick matter, 

 which rapidly dries and forms scabs. The horse is dull and dejected, 

 loses its appetite, and has a rough dry coat with the hairs on end. 

 There is moderate thirst. The respirations are somewhat quickened 

 and the pulse becomes rapid and full. The body temperature is ele- 

 vated, frequently reaching lO-i^ or 105° F., within thirty six or forty- 

 eight hours from the appearance of the first symptoms. 



The visible mucous membranes, especially the conjunctivae, are of a 

 bright rosy red. In the lymphatic, cold-blooded, and more common 

 horses these symptoms of fever are less marked; even with a compara- 

 tively high temperature the animal may retain its appetite and even 

 work comparatively well, but these cases, if worked and overheated, 

 are apt to develop serious complications. 



At the end of from three and a half to four days the eruption breaks 

 out, the fever abates, and the general symptoms improve. The eruption 

 in severe cases may be generalized ; it may be confined to the softer 

 skin of the nose and lips, the genital organs, and the inside of the thighs, 

 or it may be localized in the neighborhood of a wound or in the irri- 

 tated skin of a pair of greasy heels. It consists of a greater or less 

 number of little nodes which, on a mucous membrane, as in the nostrils 

 or vagina, or on soft unpigmented skin, appear red and feel at first like 

 shot under the epidermis. These nodes soften and show a yellowish 

 spot in the center when they become pustules. The epidermis is dis- 

 solved and the matter escapes as a viscid fluid at first citrine and later 

 cloudy and purulent, which dries rapidly, forming scabs; if these fall 



