Etiology. Symptoms. 325 



Etiology. Jenner searclied for the source of cow pox in 

 horse pox, and did so in that form of the disease which is mani- 

 fested as a vesicular eruption in the posterior part of the pas- 

 tern. Later, as has been mentioned, the disease was identified 

 with pustular stomatitis or dermatitis, and therefore the infec- 

 tion experiments supposedly carried out with horse pox virus 

 must be regarded as indecisive. 



Loy transmitted horse pox successfully to man in seven cases, and Hertwig, 

 also Pingaud observed the natural transmission of horse pox to man. Recently 

 Cameron (1908) reported a case in which on the arm of a driver who treated a 

 horse affected with pustular stomatitis, a pox eruption developed. Chanveau, on 

 the other hand, produced general pox eruptions in older horses, by injections of 

 vaccine into the lymph vessels, and in young animals with an injection into the 

 blood circulation (large vesicles developed especially on the nostrils, lips and on 

 the rump; they first appeared eight days after the infection). Similar results 

 were obtained in transmission experiments by Warlemont and Pfeififer. 



Symptoms. At the present time the vesico-pustular exan- 

 thema, in the flexor region of the pastern of young animals, is 

 considered as horse pox, in which it is supposed that the disease 

 is transmitted to the skin of the pastern principally during 

 shoeing by the hands of the blacksmiths and drivers (Fried- 

 berger & Frohner). The sensitiveness of the pastern, and the 

 functional disturbance of the extremities produced by this, 

 sometimes also a febrile elevation of the body temperature, 

 indicate the development of the affection. The skin on the pos- 

 terior surface of the pastern is swollen and reddened, soon 

 vesicles develop to the size of a lentil, which burst shortly after, 

 whereupon scabs develop on the reddened, moist epidermis, 

 under which new epithelium forms. In rare cases the eruption 

 develops also on other parts of the body, as on the head, espe- 

 cially around the opening of the mouth and nostrils, exception- 

 ally also on the mucous membrane (Berger observed the appear- 

 ance of pox in 15 horses on the conjunctiva). 



Diagnosis. A disease which is manifested with the above 

 symptoms could be considered as pox and differentiated from 

 the common exanthema of the pastern only when typical pox 

 vesicles develop on the affected part of the skin, or when the 

 inoculation of the contents of the vesicles produces a typical 

 eruption of pox on the skin of cattle. From the standpoint of 

 differential diagnosis the contagious pustular dermatitis, coital 

 exanthema, and the contagious pustular stomatitis come into 

 consideration. 



Literature. Jenner, s. p. 318. — Bouley, Diet, de med. vet., 1871, IX, 451. — 

 Chauveau, Rec, 1866, 305 u. 625.— Hertwig, Chirurgie, 1874, 182 (Lit.).— Dieckerhofif, 

 Spez. Path., 1892, I, 999. — Nocard & Leclainche, Maladies microb. des animaux, 

 1903, I, 598.— Cameron, Brit. med. J., 1908, I, 1292. 



(d) Swine Pox. Variola suilla. 



Occurrence. Swine pox represents a very rare disease. In 

 some years it appears to occur in certain parts of Southern 

 Hungary with considerable frequency (in 1907 it existed in 



