DISINFESTATION 61 



live and thrive within a few inches of them. It 

 is therefore imperative in using repellant sub- 

 stances to either smear the body over with them 

 or to impregnate the clothing. Several are suit- 

 able for this. The naphthalene paste described 

 below may be smeared over the inside of the 

 underclothing, especially along the seams. N.C.I. 

 powder as used in the Army has also a repellant 

 action on lice. One or other of these substances 

 should undoubtedly be used generously by any 

 one whose duty it is to work amongst the sick 

 in any louse-borne epidemic, even if louse-proof 

 overalls are worn. In their absence any grease 

 is an advantage, even rancid butter being used 

 by some people. 



Very many substances have been recommended 

 from time to time for the destruction of lice on 

 clothing and the body, and a few of these will be 

 mentioned here. 



Lysol is- a well-known standard disinfectant 

 which may be purchased from any chemist or 

 prepared by heating together for half an hour 

 equal parts of crude carbolic acid and soft soap. 

 This is used in a 2 per cent solution (1 table- 

 spoonful in 2 1 pints of water) for the destruction 

 of lice. At all ordinary temperatures this kills 

 nits in half an hour if the garments containing 

 them are steeped in the solution. The lice, how- 

 ever, survive if the temperature of the fluid is 

 below blood heat, and it should therefore for 

 safety have a temperature of about 104 F. 



