194 



ZOOLOGY. 



the old ones in almost all particulars ; there is no true 

 metamorphosis. All lice have a kind of proboscis, 

 which can be protruded and retracted, and upon which 

 are placed the mouth-parts, which enable it to be used 

 for sucking or biting. According to the last feature 

 a distinction can be drawn be- 

 tween true or blood-sucking lice 

 and biting lice or fur-eaters, which 

 devour small scales derived from 

 the skin or else bits of hair and 

 Jeathers. Lice multiply very 

 rapidly on the bodies of human 

 beings and animals when insuffi- 

 ciently cleansed, and under these 

 circumstances more on sick and 

 ill-nourished individuals than on 

 those which are healthy and well 

 nourished. It is obvious that the 

 true, blood-sucking lice usually 

 injure their host more than the 

 biting lice, which, however, especially when present 

 in large numbers, may cause an intolerable and in- 

 jurious itching by their movements here and there. 

 Preventive Measures: Suitable feeding and treat- 

 ment. Proper care of the skin. Remedies : Repeated 

 combing with a comb which has been dipped into 

 a solution of soda. Rubbing the badly infested 

 spots with soft soap and soda, washing them out after 

 twenty-four hours. . Among other washes are — 6 parts 

 soft soap, 1 part benzine, 10 to 15 parts water; or 

 tobacco water, 1 part of common tobacco in 20 to 25 

 parts water ; arsenious acid, in various mixtures, e.g. in 

 Bigg's Composition (p. 193). Employ the muzzle. 



Fig. 122. — Horse Louse 

 (HtemafopmMS macro- 

 cephatits), magnified ten 

 times. 



