4 
SHEEP SCAB. 
ter, to make extensive tests of the more promising dips by 
treating a thousand or more scabby sheep in each.* 
SYMPTOMS OF THE DISEASE. 
The infection nearly always occurs along the back of the 
sheep between the base of the neck and the tail. Bad patches 
sometimes occur well down on the side of the sheep and even 
upon the tail. The presence of the mites causes uneasiness and, 
apparently, intense itching, which the animal endeavors to re- 
lieve by pulling the wool from the infested spot with its teeth 
(^‘digging”), or by rubbing. The first indication is usually a 
small loose lock of wool projecting from some place upon the 
side or back of the sheep. If not attended to, the scabby spot 
increases rapidly in size and the continual pulling entirely re- 
moves the wool so that there is soon a bare spot of greater 
or less extent. Fortunately the mites are gregarious in habit, 
i. e., living in colonies and not scattering themselves over the 
sheep generally, so that a thorough treatment of the infested 
spot will usually result in a permanent cure unless re-infection 
takes place from some other animal. 
When a spot is just starting with, perhaps, a single mite 
upon it, it can be detected by one who has had a little ex- 
perience, from the pale or yellowish color of the skin and its 
moist surface, due to an exudation of serum. The certain test 
is to actually find the mite or mites present, which is not a 
difficult matter if one has a fairly good hand lens. 
A little later this patch will have increased in size, the 
central portion will be covered with a yellowish scaly or mealy 
material somewhat resembling dandruff, produced by the dry- 
ing of the serum. Finally these spots become thickly covered 
with scales or ‘‘scabs,” and the mites mostly migrate into the 
wool about the margin, where, with their eggs, they often al- 
most cover the skin. I have seldom found mites or eggs under- 
very heavy scab. Sometimes a heavy reddish scab, indicating 
the presence of blood and an open sore, are found, but such 
cases are not common in my experience. 
HOW THE DISEASE IS SPREAD. 
As the disease is caused by a living creature that is able 
to crawl freely about and to live for several days, either in 
the egg or mature state, off the body of the sheep, it is easy 
to understand how the infection may spread from animal to ani- 
*The manufacturers of Zenoleum and Skabcura have already offered their 
dips in any quantity desired for a test, free. This certainly shows the confi- 
dence these manufacturers have in their respective dips. 
