EXPERIMENTS MADE ON SHEEP WITH THE INSECT, &C. 633 
which contained ten vigorous insects of both sexes. The sur- 
rounding wool was then pressed over the inoculated part, and the 
sheep were penned in a separate clean stall. On the 2d day, i. e., 
October the 8th, eight insects were seen which had crept amongst 
the surrounding old wool : two of them could not be found ; each 
of them were living. The skin on the spot was redder and warmer 
than natural. — 3d day (October the 9th). The insects have all 
disappeared ; not one can be found upon the hide. The spot upon 
which the experiment has been performed is covered with a thin 
yellow scurf, which allows itself to be loosened with the point of a 
knife, and the skin underneath appears of a bluish red ; the spot 
also appears a little swollen. This scurf seems not to have been 
the result of the infection, but the irritation produced upon the skin 
by pulling off the wool. — From the 4th to the 6th day, i. e., from 
the 10th to the 12th of October, the parts appeared to be in the 
same condition as above. — On the 7th day, October 13th, things 
were nearly the same, but the scurf had become browner and 
harder, and in the neighbourhood of the raised spot, which was 
still covered with wool, there were many little superficial hard 
rough spots, about 2-10ths of an inch in size, in which the colour 
had become bluish, and inflammation seemed to have commenced. 
— On the 8th and 9th day, i. e., October 14th and 15th, appear- 
ances were as on the preceding days — On the 10th day, i. e., 
October the 16th, under the scurf several insects made their ap- 
pearance ; the hide was itself harder, and all around the spot there 
were small yellow brown scabs. In all these places the sheep 
seemed to itch by attempting to rub themselves, and when the part 
was scratched by the nail the animal shewed pleasure by the well- 
known motion of the lips. — From the 11th to the 15th day, i. e., 
from the 17th to the 2lst of October, things remain exactly as last 
reported, excepting that the disease is greater in degree and has 
spread further. — 16th, 17th, and 18th, from the 21st to the 24th 
October, much the same. The extent of the scab in the infected 
part is now about two square inches, and at every point covered 
over with scab, under which an abundance of insects are disco- 
vered. — From the 19th to the 21st day, i. e., from October 25th to 
the 27th, the same, excepting that the disease continues to spread. 
— 21st to 32d, i. e., from October the 28th to November 7th, the 
same : the part now covered with scab is twice the extent of that 
first infected. — From the 33d to the 38th day, i. e., from the 7th to 
the 13th of November, the scab continued to extend more and 
more, so that on the 39th day (14th November) the scab had ex- 
tended over the greatest part of the back. The scurf is in different 
parts of different thickness and colour, principally yellow-brown, 
about half-an-inch thick, firm, and, on account of its transparency, 
