588 EXPERIMENTS MADE ON SHEEP WITH THE INSECT. 
been exposed to infection and the outbreak of the scab. Waby 
himself has made no mention of this last, but the result of his ex- 
periments gives the necessary data. As these experiments were 
the only ones made on the subject, I determined to repeat them, 
and further, to investigate the subject by, in some degree, modify- 
ing them. They were undertaken in the spring of 1827 and in the 
winter of 1827-8, under the eye and with the assistance of the 
other teachers of the Royal Veterinary School, and they may 
therefore on this account be considered as worthy of implicit con- 
fidence. 
1st. — The three sheep from whom the infection was taken were, 
on the 5th of October, 1827, bought of a man at Henningsdorf, 
seven and a half miles from Berlin, and were taken to Berlin in a 
cart : they were each immediately placed in a separate stall at the 
Veterinary School, and a different superintendent was appointed 
for each : they were each three years of age, apparently well-fed, 
and in a moderate degree affected with the scab. There was upon 
each the small swellings as well as scurf, together with sore places 
and a number of insects, which under the microscope appeared 
exactly like those described by Waby. No evidence was afforded. 
Neither of these sheep had contracted the scab spontaneously or 
through infection. 
2d. — The three sheep inoculated and marked 1, 2, and 3, were 
four year old good wethers, which, on the 1st October, were chosen 
from amongst thirty that were sold to the butcher for slaughter. 
They came from a situation where there was no scab amongst 
the sheep, and were in very good health, and on the very day 
were brought to the Veterinary School. We satisfied ourselves, 
both by strict inspection and by observing them for some time, that 
they were perfectly free from the disease. These sheep also had 
each a separate stall, and three different persons to attend them. 
3d. — The six other sheep that were inoculated, and which were 
numbered 4, 5, 6, 7, 8, 9, were chosen, on the 2d of October, from 
a fine flock of M. Grafen, of H . To my certain knowledge, 
for at least five years they had had no scab nor any kind of disease 
of their hide ; and, at the time of the experiments, not the slightest 
disease could be discovered. These also were placed each in se- 
parate stalls, and had a distinct attendant. 
4th. — The food of all the above sheep was 31bs. of excellent 
hay, and their drink pure fresh water; and they were littered 
abundantly with clean and quite fresh straw. 
5th. — All the sheep remained constantly in their stalls, except- 
ing only for the purpose of performing the experiments and the 
daily observation of the effects of inoculation. 
6th. — The operation and the daily examination of the sheep was 
