TRENCH FEVER 129 



have proved. In this we see how dangerous a 

 proceeding may be the homely shaking of a 

 blanket used by one who is lousy and a sufferer 

 from the disease. 



Adult lice, given two full meals a day and kept 

 at the temperature which exists inside the clothing, 

 each produce daily about eighty fragments of the 

 granular dust into which the excreta ultimately 

 breaks up (Fig. 9). The female louse produces 

 rather more than the male. One thousand of these 

 granules weigh three milligrams. During its life 

 of about forty days the louse therefore produces 

 about ten milligrams. Since it may be transmit- 

 ting trench fever for the whole of its life, after 

 the shorter or longer incubation period of the 

 virus of the disease in its body, practically the 

 whole of this dust may be of a most dangerous 

 nature, and since we have shown that one-tenth 

 of a milligram is enough to cause an attack of the 

 disease a single louse may produce sufficient to 

 infect almost a hundred men. A soldier who 

 harbours in his clothing five hundred lice, a by 

 no means exceptional number, and has the trench 

 fever germ in his blood, is the indirect means of 

 producing enough infected louse excreta daily to 

 cause an attack of the disease in every man in his 

 battalion, and while much of this is retained in 

 his own clothing much of it is also spread abroad 

 and falls on his comrades. 



But still, without the lice there could be no 

 droppings, so that all our energies should be 



K 



