DISEASES OF THE HORSE. 525 



Symjytoms. — There is a period of incubation, after an animal has 

 been exposed, of from live to eight daj^s, during which there is no 

 appreciable alteration in the health. This period is shorter in summer 

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

 point of inoculation and the animal becomes feverish. 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 some- 

 what quickened and the pulse becomes rapid and full. The body 

 temperature is elevated, frequently reaching 104° 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- 

 ti^'el}" 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 sj'mptoms improve. The erup- 

 tion 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 irritated skin of a pair of greasy heels. It consists of a vary- 

 ing 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 epider- 

 mis is dissolved and the matter escapes as a viscid fluid at first citrine 

 and later cloudy and purulent, which dries rapidl}', forming scabs; if 

 those fall off or are removed they leave a little shallow concave ulcer 

 wliicli heals in the course of five or six days. In the softer skin if 

 pigmented the cicatrices are white and frequently remain so for about 

 a 3'ear, when the pigment returns. The lips or genital organs of a 

 colored horse, if covered with a number of small white spots about 

 the size of a pea, will usuall}^ indicate that the animal has been affected 

 with the horsepox. 



At times the pustules may become confluent and produce large super- 

 ficial serpentine ulcers on the membrane of the nostrils, around the 

 lips or e3'elids, or on the borders of wounds and in greasy heels; in 

 this case the part becomes swollen, hot, painful, and is covered with 

 a profuse discharge of matter. In this form there is f requentl}^ a sec- 

 ondar}^ fever lasting for a day or two. 



In severe cases there may be a suppurative adenitis, or inflammation 

 of the lymphatic glands which are fed from the affected part. If the 

 eruption is around the nostrils and lips, the glands between the jaws 



