42 NEW YORK STATE MUSEUM 



Lice are killed in 3 hours at a temperature of 113 F., in i l / 2 hours 

 at a temperature of 122 F., in 20 to 30 minutes at a temperature of 

 140 F., and in 5 to 10 minutes at 177 F. The eggs require a little 

 longer treatment. In practice, one hour at 140 F. should be 

 sufficient. 13 A 10 minute exposure to a temperature of 160 F. 

 kills the nits with certainty. 14 It is probable that neither lice nor 

 eggs can survive an exposure to 140 F. for a period of 30 minutes, 

 and the only reason for prolonging the treatment with higher tem- 

 peratures is to insure that this minimum be attained in all parts 

 of the clothing or other material treated. 



Some idea of the fecundity and prevalence of this pest may be 

 gained from the above and prepare us for believing that 95 per 

 cent of a battalion which had seen 6 months service were found 

 lousy, the average number of lice per man being 20, and 5 per cent 

 were dangerous carriers, each bearing between 100 and 300 lice, 

 and that in exceptional cases over 20,000 lice and eggs may be found 

 upon a badly infested garment. 15 These parasites make the men 

 uncomfortable, seriously interfere with sleep, and thus decrease 

 efficiency to a material extent, not to mention the possibilities of 

 their carrying disease. 



A careful study of the problem lfi shows that living-places 'such as 

 dugouts, billets and bivouacs are of comparatively slight importance 

 in disseminating this pest, and the same is true of such materials as 

 blankets, straw and bedding. The infested soldier, his clothing 

 and kit, due to the intimate association inevitable under camp con- 

 ditions, appears to be by far the most important source of infesta- 

 tion. The parasites, as noted above, may be transferred by the 

 wind from soldiers to medical inspectors, and the ordinary dressing 

 and undressing in tents may easily result in dislodging the pests and 

 infesting tentmates or chance companions. Any large assemblage 

 of recruits is likely to contain a few verminous individuals, possibly 

 unconscious of their condition, and these are in most instances the 

 primary cause of the trouble, which is greatly aggravated in many 

 instances by the limited sanitation possible under camp conditions. 

 Personal cleanliness, such as bathing and frequent changes of under- 

 wear, especially if precautions are adopted to prevent infestation 

 from verminous individuals, are important control measures. The 

 wearing of silk underclothes is one of the best preventives. 17 



1:1 Hevmann. Bui. Inst. Pasteur, 14:01. iQi6. 



l4 Kisskalt & Friedmann. Deutsch. Med. Wochenschr., p. 154. 1915. 



15 Peacock. Brit. Med. Jour., 2892, p. 784^88. 



16 Peacock. Brit. Med. Jour. 2892, p. 784-88. 



17 Kisskalt Deutsch. Med. Wockenschr., p. 154. 1915. 



