348 SCAB IN SHEEP. 



Youatt describes the appearances as very uncertain and incon- 

 clusive. He says there is generally chronic inflammation of the 

 intestines, with the presence of a great number of worms ; the 

 liver is occasionally schirrous, and the spleen enlarged ; and there 

 are frequently serous effusions in the belly, and sometimes in the 

 chest. There has been evident sympathy between the digestive 

 and cutaneous systems. Several of these appearances, however, 

 are observed in ill-nursed lambs and old sheep dying of poverty, 

 although free of scab. In the former, the intestines are often in- 

 vaded with worms to a great extent, and water is found both in 

 the. belly and chest; whereas, in old sheep dying of poverty, water 

 is very often in the chest. I once slaughtered a strayed sheep 

 effected with scab, to prevent the disease from spreading amongst 

 the flock I had the charge of, and found no trace of disease in- 

 ternally; all the organs were apparently healthy; the animal 

 affected, however, was in the first stage of the disorder. 



It is clearly ascertained by scientific men that the scab 

 in sheep, like the itch in the human being, is connected with 

 and propagated by certain minute insects belonging to the 

 class of acari, which inhabit pimples or pustules. But the 

 question naturally arises, How came they first into existence ? 

 This problem is very difficult of solution, and puzzles the most 

 eminent physiologists. But, as I have already said, I have 

 never known it break out spontaneously amongst a flock of 

 sheep properly managed, during a period of thirty years' experi- 

 ence as a shepherd in pastoral districts. This fact alone, I think, 

 is conclusive proof that its origin must be sought for in mis- 

 management. To show what kind of mismanagement is most 

 liable to produce the disease, I will quote the authority of my late 

 employer, Mr Gardner, who was at one time and for many years 

 a large flock-master in Australia, where the disease prevailed to 

 a great extent. Amongst settlers in Australia the idea was com- 

 mon that when sheep were heated by being overrun with dogs, 

 and being huddled close together into folds all night, as was the 

 custom in the colony, the heating and overcrowding, combined 

 with the fold at times getting foul or dirty, had a great influence 

 in producing the disease in that warm country. 



Mr Gardner, however, states from his own experience that he 

 generally could trace scab amongst his own flock to have been com- 

 municated from buying sheep affected with scab, or having come in 

 contact with some neighbouring flocks so affected. Nevertheless, it 

 is quite evident that overheating or overcrowding in folds, espe- 

 cially the latter, has a tendency to bring on disease of the skin. 

 A strong proof of this fact came under my own observation on 

 several occasions. It was the practise on the farm of Traquair 

 Knowe, for several years to draw from the stock a few of the 

 worst conditioned and unthriving sheep in the month of October, 



