09 BOARD OF AGRICULTURE. 



least three times, at intervals of three or four days, to destroy 

 the young as fast as they hatch. 



Species of Sarcoptes, closely allied to the itch-insect, have 

 been found on the domestic animals, causing diseases analo- 

 gous to the itch in man. Such diseases, caused by quite a 

 number of distinct parasites, are called " mange." They 

 have been observed on the cat, dog, camel,* and hog. 



The genus Dermatodectes is closely allied to Sarcoples, and 

 the species likewise live on animals, burrowing in the skin. 

 D. bovis infests cattle, and D. ovis lives in the skin of sheep. 

 The genus Dermaleichus infests birds in a similar manner. 



All these parasites should be treated like the itch-insect of 

 man. The sulphuret of potassium solution, applied with a 

 brush that has long bristles, like a white-wash brush, is 

 probably the best and simplest remedy. 



The Face^mile (Demodex folliculorum Owen). Figure 48. 



This singular but minute parasite lives in the diseased and 

 enlarged follicles in the skin of the human face, especially in 

 those about the nose and chin. The follicles, when thus dis- 

 eased, are enlarged and filled with a thickened 

 sebaceous matter, the orifice being usually ob- ri s ure 48 - 

 structed by a hardened, blackish substance. If 

 these be pressed, and the matter which is forced out 

 be carefully examined with a microscope, it will often 

 be found to contain numerous specimens of this minute 

 creature, in all stages of development. A drop of 

 oil or ether applied to the sebaceous matter, to 

 dissolve the fatty parts, will render them more 

 readily visible. The young ones have but six short 

 legs ; the adults have eight legs and a worm-like 

 body, as represented in Figure 48. It has been thought that 

 the " barber's itch" is caused by this parasite, but I do not 

 know that this has been fully established. 



*S. dromedarii, of the camel, is sometimes communicated to man, causing a 

 form of itch worse than the ordinary, owing to its great size and numerous spines. 



Figure 48. Face-mite (Demodex folliculorum Owen, or Simonea folliculorum of 

 some authors), much enlarged. From Packard's Guide. 



