SCAB, OR ITCH, 371 



fully, with soap and water ; and after that, on the second day, 

 with a wash of lime-water and tobacco decoction, of equal 

 parts. 



The ordinary scab in sheep is much akin to the mange in 

 other animals. It is most common in the spring and early 

 part of the summer. It may be produced by a variety of 

 causes, such as bad heep, and exposure to cold and wet weather ; 

 thus producing suppression of the perspiration. The pre- 

 vailing cause, however, is contagion. 



Symptoms. — The sheep is restless — scratching and nib- 

 bling itself, and tearing off the wool. When closely exam- 

 ined, the skin will be found to be red and rough. Numerous 

 pustules have broken and run together, and form small or 

 large patches of crust or scab — hence the name of the disease. 

 The shoulders and the back, most frequently, earliest exhibit 

 these pustules. The general health of the animal is affected 

 according to the extent and virulemce of the eruption ; some- 

 times he pines away and dies, exhausted by continued irri- 

 tation and suffering. It is a most contagious disease. If it 

 is once introduced into a flock, the farmer may be assured 

 that, unless the diseased sheep are immediately removed, the 

 whole of his flock will become infected. 



It seems to spread among the sheep, not so much by di- 

 rect contact as by means of the rubbing-places ; for it has 

 happened, that when a farmer has got rid of his tainted flock, 

 and covered his pastures with a new one, the disease has bro- 

 ken out again ; and this has arisen from contact of the sheep 

 with the old scratching places of fences, trees, and so forth. 



" After it was found that the itch in the human race was 

 caused by an insect, a species of Acarus, it was supposed that 

 similar cutaneous diseases in animals might arise from the 

 same source. M. Walz, a German, was the first to establish 

 this point and fully investigate its character, and numerous 

 subsequent examinations have proved the correctness of his 

 opinions. He found that the scab, like the itch, mange, &c., 

 is caused by animalculae ; that the irritation caused by his 

 burrowing in the skin, forms the pustule, and that when this 

 breaks, the acarus leaves his habitation and travels to anoth- 

 er part of the skin, and thus extends the disease. When 

 one of these acari is placed on the wool of a sound animal, 

 they quickly travel to its roots, where the place of burying 

 themselves is shown by a minute red point. About the six- 

 teenth day the pimple or pustule breaks, and if the acari is 



