358 VETERINARY HYGIENE 



depreciation in the value of the fleeces and great dislocation of the 

 sheep trade, as well as a considerable pecuniary burden that has to 

 be borne by the general public. In dairy byres mange is very 

 common in some districts and is the cause of loss of milk and 

 general unthrivitiness of the affected cows. A byre full of mangy 

 milch cows is not a pleasing sight when there is a possibility of 

 having to drink the milk. 



Differences in the Mode of Life of the Mange Parasites. 

 Psoroptes live on the surface of the skin but suck their nourishment 

 from it. Sarcoptes possess biting jaws and the ovigerous females 

 burrow. The Chorioptes or Symbiotes are scale-eating mites and 

 neither puncture nor burrow into the epidermis. While mange 

 parasites may be found on any part of the body, the majority of 

 sarcopt cases are primarily localised in one of three places, withers, 

 throat or inside of thighs. Symbiotes are primarily found on the 

 extremities, especially on the hind legs, but if neglected they extend 

 over a large body area. 



Though diagnostic methods have no place in such a book 

 as this, it may nevertheless be urged that appropriate measures 

 be taken first to be certain that mange does exist, and second, if 

 present to determine its nature. Mange cannot be diagnosed by 

 scratching an animal with the end of a stick, and " evidence " so 

 obtained should not be accepted by any authority. 



Incidence. The first Mange Order came into force in 1912, 

 and the returns for that year show that in Great Britain there were 

 2873 outbreaks with 6608 animals attacked. In 1913 the number 

 of animals attacked was reduced to 4467. During a part of 1913 

 and a part of 1914 the Order was suspended. In 1916 there were 

 2147 outbreaks affecting 4689 animals; in 1917, 2614 outbreaks 

 with 4873 animals. In 1918 the disease increased to such an extent 

 that the official returns show 4483 outbreaks involving 8422 animals. 



Ireland is, as indicated by the returns, comparatively free from 

 mange. In 1912 there were 69 outbreaks with 121 animals attacked, 

 and in 1916, 74 outbreaks with 106 animals affected. 



Mange is more common in towns than in the country, though the 

 scarcity of horses during the war led many farmers to purchase 

 low-priced animals from town sales in order to carry them through 

 hard working periods. Such purchases sometimes resulted in 

 the infection of farm studs where previously the disease was 

 unknown. 



With regard to seasonal incidence, the official returns show 

 that mange is at its height during December, January and February. 

 March shows the beginning of the decline, which continues through- 



