CHAP. III. 



SHEEP SCAB. 



585 



and excoriated, or, in more advanced disease, deep sores are found, as 

 well as fragments of skin in a dead and sloughing condition. Small 

 red raised spots are also observed here and there marking fresh points 

 of attack of the parasite. The diagnostic indication of the disease is 

 the discovery of the acarus. This may be made by taking a portion of 

 the scab and examining it under a lens of moderate power ; or if placed 



Fig. 151. Mature Female Acarus, from a Sheep affected with Scab. 



(Drawn with the camera. Magnified 100 diameters.) 



on a piece of black paper near the fire the acari may be seen with the 

 unaided eye moving towards the warmth. 



Treatment. Various agents are employed in the treatment of this 

 disease such as decoction of tobacco with sulphur, or lime with 

 sulphur, or corrosive sublimate, mercurial ointment, arsenic, &c. The 

 least troublesome and most inexpensive mode of dealing with an 

 infected flock is to use one of the many preparations of " sheep-dipping 

 composition " now so largely sold by druggists and others. 



Pastures, buildings, yards, sneds, pens, &c., in which scabby sheep 



