YARiOLA ovm^. 213 



tliat variola ovinse is inoculable, contagious, and infectious, and 

 that its incubative stage varies from seven to thirteen days 

 when communicated by inoculation, and from nine to twelve 

 days in natural cases. 



Like the poison of cattle plague, that of sheep-pox is both 

 volatile and fixed, existing in the blood, the tissues, secretions, 

 and emanations, and may be carried from place to place in the 

 clothes of attendants, in fodder, wool, skins, and particularly by 

 dogs. Mr. Chas, Percivall informed Mr. Gamgee that he had 

 seen a dog (Mr. Stephen Neate's) suffering from symptoms of 

 disease identical with those of variola ovinse, and there could be 

 no doubt but that the dog contracted the disease from affected 

 sheep {DGmestic Animals) ; and it is pretty well demonstrated 

 that a healthy flock is not secure from the disease at the distance 

 of a quarter of a mile from affected sheep. Upon this head 

 Continental writers are very clear, and they point out the 

 danger of driving a healthy flock on the same road which shortly 

 before has been travelled over by a diseased one. Chauveau has 

 shown that the virus is a hundred times more infective, that the 

 matter contains in an equal quantity thirty times the number 

 of corpuscles, and is more active than that of vaccina. He has 

 also shown that if vaccine matter be diluted with fifty times its 

 weight of water, it propagates itself when inoculated with great 

 uncertainty, while ovine matter may be diluted 1500 times before 

 its virulence is appreciably affected. 



The virus retains its vitality, when protected from the air, for 

 a very considerable period, but is destroyed by the influence of 

 air, heavy dews or rain, sunlight, a temperature of 122° F. frost, 

 and disinfectants, such as chlorine, permanganate of j)otash, and 

 ozone, as well as by putrefaction, and if the wounds be suppurat- 

 ing, the matter from them will not infect. 



PATHOLOGY AXD SYMPTOMS. 



As already stated, the period of incubation varies from about 

 the seventh to the thirteenth day, during which time there are 

 no symptoms observable to a non-professional person. Like 

 all specific fevers, however, there is an increase in the tempera- 

 ture of the animal body for some time prior to the outward 

 manifestation of the disease. In thirty-six to forty-eight hours 

 after the first manifestation of the disease, the temperature rises to 



