230 DISEASES OF SHEEP. 



should be as carefully applied over every part as it would be in the 

 act of" smearing-, for the vermin will speedily collect and burrow in 

 any spot which the ointment may not have reached. 



The tick is many times as large as the louse, but not so frequently 

 found. When not gorged with blood it is flat, but when bloated it is 

 round, and brown or black, and varies in size from a pin's head to a 

 small bean. When one of them fastens itself upon the sheep, it 

 seems to retain precisely the same situation for some weeks, or even 

 months, and yet the young ticks are found round the old ones, resem 

 bling numerous red points, but becoming brown as they increase in 

 size. They, too, select the sheep that is debilitated by want of pro- 

 per nourishment or by disease. 



The tick is more frequent on some grounds than on others. On 

 some farms, even although badly managed, it is seldom found ; on 

 others it is scarcely to be got rid of, even although the sheep should 

 be healthy. It would seem as though it were bred in the ground, 

 and that one part only of its existence is spent on the sheep. Some 

 shepherds set diligently to work, and pick them off. This, however, 

 is an almost endless task. Others dress the sheep with turpentine, 

 which usually destroys them; but the scab ointment is the surest 

 remedy, as well as preventive. 



The sheep is tormented by two species of flies. The one endea- 

 vours to lay its eggs on the muzzle, and thence, speedily hatched by 

 the moisture and warmth of the breath, the animalcule, or larva, 

 creeps up the nostril, and finds its way into the frontal sinuses, or 

 some of the cells above the nose, and there fastens itself, and lives 

 and grows, until it becom.es a large worm : it then creeps again down 

 the nostril, assumes the form of a grub, burrows in the earth, and in 

 due time appears in the form of a fly. It is only during the time of 

 the depositing of the egg that the sheep are disturbed or injured, and 

 then they may be seen huddling together on the barest part of the 

 pasture, with their noses close to the ground, and by continual shaking 

 of the head and stamping, endeavouring to prevent the depositing of 

 the egg. When the little worm has reached its destined situation, it 

 seems no longer to trouble the animal; and these bofs rre found in 

 the heads of some of the largest and fattest sheep. This is the des- 

 tined place of this worm, and nature would not make it destructive, 

 or even much annoying, to the animal by wliich it is to be supported. 



Another species of fly, or perhaps several other species, are far 

 more troublesome and injurious. At some uncertain time after shear- 

 ing, and seemingly oftener occurring to those that were early tlian to 

 those that were later sheared, the sheep will be struck with the fiy. 

 This will be discovered by the uneasiness of the animal. It is not 

 the itching of scab, for it is before the usual appearance of that dis- 

 ease, and when the sheep was shorn there was not the least appear- 

 ance of it. The sheep will hang down their heads, stand for awhile 

 as if listening, then bow up their backs, violently shake their tails, 

 stamp furiously with their feet, gallop away for a short distance, and 



