636 EXPERIMENTS MADE ON SHEEP WITH THE INSECT, &C. 
October : The condition of the animal is in no way changed. — 
15th day, 21st of October : As before ; much of the scurf, how- 
ever, on being carefully separated there was discovered no insects 
underneath : the skin under the scurf was moist, with some ap- 
pearance of inflammation around. 16th to 17th day, 22d to 23d 
of October : The same. — 18th day, October 24 : Much the same. 
By the most careful inspection no insect could be found. The 
scurf now begins to loosen, and it has in no way increased in 
extent. — 19th day, 25th of October : The same as yesterday. — 
20th day, October 26 : The scurf comes off spontaneously, and 
the skin appears sound underneath. — 21st day, October 27 : New 
wool now begins to sprout up. — 22d to 26th day, from October 28 
to November 1 : The wool is growing in a perfectly natural 
manner. 
Experiment No. 5 ( repetition of the former ). 
The former inoculation for twenty-six days after the former date 
having shewn no tendency to produce the scab, the experiment was 
on the 2d of November, at nine o’clock in the forenoon, repeated 
on the same sheep in the following manner : — About the middle of 
the left shoulder-blade, and in the neighbourhood of the left flank, 
the wool was clipped off from the skin as close as possible. The 
skin on the first spot was left whole, and was only moderately 
rubbed with the hand for a minute, for the purpose of causing the 
matter to be applied to remain in contact with it. The other spot, 
however, was punctured in three different places, and some friction 
applied. Then some matter, taken from under the scab of a sheep 
much affected, was by means of the blade of a knife applied to 
both spots, and gently rubbed upon them ; then the wool surround- 
ing the spots was brought together. Neither the naked eye nor 
the help of a microscope could discover a single insect among the 
matter. 
The removal of the wool in the foregoing experiment produced 
considerable irritation, and caused a good deal of yellow scurf to 
be formed. To make sure that this was the cause of the above 
effects, to-day, at two spots on the right side of the belly and breast 
of the same sheep, some wool was pulled off without applying any 
of the matter. — 2d day, Nov. 3d : at both spots on which the 
matter has been applied the skin is warmer and redder than the 
surrounding parts, but there is no knotty hardness to be felt. The 
skin is a little more moist around. Where the incisions were 
made there is a dark bloody scab. Both the naked spots on the 
right side of the body where the wool was simply removed was 
exactly in the same state as in those spots where the matter was 
