62 LICE AND THEIR MENACE TO MAN 



(40 C.) ; that is, it should be distinctly hot to 

 the hand, to make certain of the complete destruc- 

 tion of the pest. If it is cooler than this, some 

 of the lice are liable " to come to life " again even 

 after the elapse of twelve hours. The advantages 

 of this treatment by solution instead of by heat 

 are that the necessary standard is more easily 

 attained in ordinary household use, and it may 

 be safely employed for articles which would be 

 damaged by great heat, such as woollen garments, 

 feathers, brushes, etc. For wholesale disinfest- 

 ation it cannot be said to compare with heat 

 in convenience. Lice killed by this means turn 

 black quickly, while the nits turn brown and 

 shrivel up. 



Paraffin (kerosene) and petrol destroy lice and 

 the nits. They are somewhat dangerous in use 

 owing to their inflammability, and petrol is, of 

 course, prohibitive at present. They are for 

 various reasons less satisfactory for the treatment 

 of garments than lysol solution. Clothing should 

 be steeped in them for half an hour to make 

 certain of the destruction of all the vermin. 



Naphthalene and soft soap was recommended 

 by Bacot and Copeman, and is used in the Army. 

 The unrefined form of the naphthalene is most 

 effective and is known as " crude un whizzed 

 naphthalene." Four parts of this are mixed 

 with one part of soft soap, resulting in an un- 

 pleasant dirty ointment which is very efficacious. 

 It should be rubbed on the inside of underclothing 



