444 THE DISEASES AND DISORDERS OP THE OX. 



longer necessary, the sheep should be placed so that they can go 

 and lie down on straw, under shelter, of their own accord. These 

 sheltering places should be provided in the fields wherein the 

 sheep are pastured. Another great point is that sheep should 

 never be " salved " in cold or wet weather. 



The way in which sheep are sometimes treated is really a very 

 great mistake, and we cannot wonder at the disastrous losses 

 which occur at times. When sheep are undergoing treatment, they 

 should be supplied with good and strengthening food, and they 

 ought to be inspected once a week until the disorder is entirely 

 suppressed. There is greater need of complete cure in the case of 

 this disorder than of some other maladies, for if only one impreg- 

 nated female Psoroptes ovis is alive on any one member of a 

 flock, the malady may spread and spread until all the sheep are 

 attacked, and even those which have been thoroughly cured, 

 may become as bad as they ever were, or even far worse. 



When we consider that these creatures can only just be seen 

 with the naked eye, we cannot wonder at the difficulty of getting 

 rid of all of them, nor perhaps even at the reckless way in which 

 some persons place the mercurial ointment on the sheep, so that, 

 even at the risk of killing large numbers of them, the disorder 

 may be put a stop to. The fact is, however, that little good, 

 but, on the contrary, a great deal of harm, is done by applying 

 large quantities of mercury, even if it be decided to risk the 

 poisoning of some sheep, and the debilitation of many, in order 

 to cure the malady. Tn any case the killing of all the parasites 

 is a question of time, and small quantities of mercury neatly and 

 carefully applied will be much more efficacious than large quan- 

 tities carelessly used. 



If any sheep should die, as may well be expected if they are 

 put under the influence of mercury in wet or cold weather, or, 

 indeed, in warm weather if the ointment be too freely used, the 

 rest of the sheep should be washed in order to remove the oint- 

 ment. If the weather be warm, the cure may be greatly facilitated 

 by shearing the sheep, for when the fleece has been removed, the 

 application which we shall mention lower down can be more 

 eflfectually applied. However, we must remember that tho pre- 

 sence of an oily or fatty substance on the skin is in itself a 

 source of danger, for the skin, when thus clogged up, cannot at 

 all well perform its due functions in the right way. The grease 



