614 SCABIES — SCAB— MANGE. 



A non-poisonous ointment may be made by taking 4 omices of oil of 

 turpentine, 6 ounces of flowers of. sulphur, and 1 lb. of lard. Mix the 

 ingredients at a gentle heat, and rub in well with the hands or with a 

 brush, at the same time breaking the crusts. The simple sulphur oint- 

 ment may be made of one part of suli)hur and four parts of lard ; one 

 fourth part of mercurial ointment may be added. Few remedies are so 

 useful as sulphur iodide, and it may well be given a trial on head scab. 



In most countries this disease has been made the subject of special 

 legislation. 



PSOROPTIC MANGE SHEEP SCAB. 



This is probably the gravest form of mange. It was described by 

 Cato the Censor in 160 b.c, by Virgil, Juvenal, Celsius, Columella, 

 Pliny, Yegetius, etc. In 1787 Abildgaard flrst showed that psoroptic 

 mange in sheep could be cured by simple external remedies, without 

 internal medications. In 1809 Walz described the causes, nature, 

 seat, and treatment of the disease. 



Since then, the parasitic, contagious nature of mange or scabies 

 has been more and more clearly recognised. 



Causation. Experience and observation have long shown that the 

 only cause is the presence of the Psoroptes communis (oris). This 

 disease is much more contagious than that just described. Psoroptic 

 mange or scabies exclusively affects those portions of the body covered 

 by the wool, and may for a long time remain unrecognised. 



The parasite is visible to the naked eye, though most inspectors 

 employ the microscope. The adult female is about 4^0 of an inch long 

 and ^Q of an inch broad ; the male is -i^ of an inch long and -^q of an 

 inch broad. The mites are discovered more easily on a dark back- 

 ground, and if a portion of the wool and crusts., is placed on black 

 paper and exposed to the sun for a few minutes the parasites will 

 generally be seen crawling about on the paper. 



The disease is transmitted directly or indirectly by contact from 

 diseased to healthy animals in the folds, fields, or sheei? runs. One dis- 

 eased sheep may contaminate an entire flock. The disease is extremely 

 contagious, and may appear even within a week after exposure. 



The parasites have exceptional vitality. It is generally stated that, 

 kept at a moderate temperature on portions of scab, the adults may 

 live from four to twenty days, but they will occasionally live much 

 longer ; cases are on record where they have lived three, four, or 

 even six weeks when separated from sheep ; if the atmosphere is dry 

 they will generally die in about fifteen days ; but death is often only 

 apparent, for the mites may sometimes be revived by warmth and 

 moisture even after six or eight weeks ; the fecundated females are 

 especially tenacious of life. 



