96 
Pasteur and his Workj 
then withdrawn and the skin lightly rubbed, in order to diffuse 
the injected material beneath it. The syringe will hold fluid 
sufficient to inoculate eight sheep or goats, or four horses or 
cows ; and with a little practice a man can operate on 150 
sheep per hour. In twelve or fourteen days after the first in- 
oculation, the operation is repeated with the second or stronger 
fluid, the opposite thigh being selected if sheep are the subjects. 
Fig. 11. — Inoculating a Sheep with the Virus. 
With the larger animals, the inoculation is made behind the 
shoulder in cows and oxen, and in the neck of horses. The 
skin being thick, care should be taken not to bruise it in 
pushing the needle through. This is best done by taking up a 
fold of the skin and passing the needle into it, the needle being 
stronger than that for sheep. If the first inoculation is not 
properly done, there is danger that the second may kill. The 
appearance of a tumour at the point of inoculation in cows has 
been rare, but in horses, and more especially young horses, 
this has been noticed ; but it has generally subsided without 
any treatment. 
The experiment of inoculating young .horses three times — 
