CHAPTEE XXI. 



SHEEP-POX. — ^FOOT-AND-MOUTH DISEASE. 



Sheep-pox. 



Sheep-pox, or variola ovina, is an acute febrile disease accompaiiied 

 by a general vesiculo-pustular eruption, bighly infectious, and 

 capable of being propagated by inoculation or clavdisation. It is 

 a common disease in some parts of Europe. In Prance the disease 

 is called la davdee, and in Italy vaccuolo. It has been introduced 

 on several occasions into this country, but has been efFectuallv 

 stamped out. As in human small-pox, there are varieties — the 

 benign and the malignant, the discrete and the confluent ; and one 

 attack is protective against the disease in future. 



It is very closely analogous to human small-pox. Vaccination 

 with cow-pox lymph has been employed to protect sheep from sheep- 

 pox, but unsuccessfully, and lymph for vaccination has been raised 

 from sheep-pox to protect human beings from small-pox. These 

 experiments were first performed in Italy. 



Marchelli, in 1802, took lymph from the vesicles of sheep-pox, and 

 inoculated children. Sacco repeated these experiments, and found 

 there was no appreciable difference from the results obtained with 

 cow-pox lymph. Dr. Legni carried on the inoculations with ovine 

 virus from arm to arm for several years, and when small-pox 

 occurred in Pesaro, it was said that all those who were inoculated 

 with the sheep virus were protected. 



Inoculation of children with ovine virus, direct from sheep, was 

 repeated by Sacco and Magnani in 1806. 



Marson in England succeeded in producing on the human 

 subject a vesicle with the physical characters of the vaccine vesicle. 

 The vesicle had a bluer tinge, and subsequent inoculation of the 

 patient with human variola was ineffectual. Other experimenters 

 were unsuccessful, but their failures, as in the case of variolation of 

 "the cow, do not invalidate the results of those who were successful. 



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