VACCINATION. 141 



and which are always far better than uncertain con- 

 jecture*." 



Hurtrel D'Arboval gives the following details, which 

 shew that on an extended scale vaccination has failed : 

 " 1523 sheep were subjected to the operation, of which 

 1341 contracted the vaccine disease, and 182 were not 

 affected. Out of the 1341 sheep, 429 were subse- 

 quently exposed to the small-pox, either by direct 

 inoculation, or by being placed among infected animals, 

 and 308 of them were attacked with the malady. He 

 infers, that the escape of the remaining 121 sheep 

 was probably to be attributed to either their non- 

 susceptibility, or to some defects in conducting the 

 experiment ; and he concludes that vaccination cannot 

 be substituted for ovinationf ." 



The principal advocate, we beheve, for the vaccina- 

 tion of sheep, is Sacco, who states "that in consequence 

 of variola o\ina prevailing to a great extent among the 

 sheep in the Apennine Alps in 1806, he determined to 

 vaccinate several of the animals, and to test the prophy- 

 lactic power of the disease thus induced by subse- 

 quent inoculation with the ovine virus. The operation 

 perfectly succeeded, and the sheep resisted the small- 

 pox, although they were mingled with an infected 

 flock." The same author likewise declares, that " he 

 has fully satisfied himself by repeated experiments of 

 the power of vaccination to destroy the susceptihiUty of 

 sheep to contract variola ; and that it has been found 

 equally protective by Hussan, Ganneron, Buniva, and 

 others." Speaking of the mild nature of the ino- 



* Hogg's Shepherd's Guide. Edinburgh, 1807, p. 246 & seq. 

 t Article Vaccination. 



