DISEASES OF THE OX AND SHEEP. 443 



this same topic, we now come to the consideration of the 

 measures which should be taken with a view to kill the little 

 creature known as the Psoroptes ovis, which produces such 

 grave mischief, and to arrest its multiplication and extension 

 to other sheep. 



In the first place, with regard to the repression of sheep- 

 scab, the measures to be taken cannot be too stringent or too 

 carefully carried out. Immediately that the disorder shows 

 itself among a flock of sheep, all the animals composing that flock 

 should at once be carefully inspected, and those sheep which 

 manifest the slightest signs of infection should be without any 

 delay taken away to a field or other quarters at a distance. 



It is advisable that all the sheep composing the flock should 

 be dressed with a suitable application. Now, for this purpose 

 farmers generally use mercurial ointments of different strengths, 

 but usually very much too strong and in too great quantity. 

 We cannot unduly emphasise the fact that sheep are very liable 

 to be actually poisoned by this process. The ordinary ointment 

 of mercury is made by rubbing together 16 parts of mercury, 16 

 parts of prepared lard, and 1 part of prepared suet, until the 

 metallic globules of the mercury can no longer be seen. It is 

 important to bear in mind that this ointment is too strong, and 

 that before being used for sheep — if farmers will use mercury at 

 all — it should be well mixed with about four or five times its 

 weight of lard. In mild cases of scabies, 3 lb. to the score of 

 full-grown slieep and 2f lb. for younger animals (about two- 

 thirds of an ounce for a lamb) is often used by shepherds. 



In order to apply this ointment, or any other unguent, the 

 wool should be parted along the back of the sheep, beginning 

 from near the head and carrying the line of parting as far as the 

 tail, and then the ointment should be neatly placed upon the 

 skin with the finger. Then, at a distance of four inches from 

 this line, another is made, and so on at intervals of four inches 

 for the whole body. It is necessary to bear in mind that the 

 mercury thus placed upon the skin is absorbed into the body, 

 and produces the effects of this drug, and consequently that, after 

 being thus dressed, the sheep should be kept under shelter for 

 some nights following, since they are likely to catch severe colds, 

 when under the influence of this dangerous substance. After 

 the night-shelter is dispensed with, as being supposed to be no 



