Gr. H. F. Nuttall 
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cases, may extend to the mucous membranes, being visible in the mouth. 
This pigmentation has at times led to a false diagnosis, the condition 
having been mistaken for Addison’s disease. As pointed out in an 
Editorial (1905, p. 234), there should be no difficulty in distinguishing 
the two conditions. In grave pediculosis there may be extensive skin 
maculae, but in Addison’s disease the pigmentation occurs in skin 
regions that are rich in natural pigment ; there are no pedicular macules 
on the mucous membrane; there are no pediculi present. Malcolm 
Morris (1911, p. 158) also notes the different distribution of the pig¬ 
mentation in Addison’s disease and the absence of the itching which 
characterizes pediculosis. Pediculosis can, moreover, be distinguished 
from scabies by the absence of lesions upon the hands and wrists. 
Pediculosis and scabies have frequently occurred together, especially 
in the course of the present war. In pediculosis the hands, forearms 
(and feet) are unaffected. The melanodermia is most marked between 
the scapulae. 
Body-lice attack infested persons chiefly at night or while at rest. 
They cause a great deal of discomfort and sleeplessness. Apart from 
the itching due to the effects of the bites and their contact with the 
clothing, especially when the body is warm, much of the discomfort 
is attributable to the insects crawling about upon the person. 
The continued restlessness and lack of sleep may induce considerable 
irritability, and children, as noted by Sobel (1913), may become 
anaemic and so run down that their school attendance is much curtailed. 
Pediculosis is a sore trial to soldiers, as all who have bad personal ex¬ 
perience will testify. 
The immediate effect of the bite varies in different persons, as is well 
known to those who have investigated the subject. This corresponds 
with what has been observed with regard to the bites of fleas, bedbugs, 
mosquitoes and other insects. Some persons state they have a “sen¬ 
sitive skin” and others that they are indifferent to the presence of lice. 
Different effects are attributed to louse-bite by various authors; 
Castellani and Chalmers (1913, p. 1578) state that after the bite 
has been inflicted, blood flows into the puncture and coagulates, a 
minute papule forms and is accompanied by much pruritus, leading 
to scratching. Sikora (vm. 1915, p. 531) denies that the bite causes 
itching, the author having been bitten about 4,000 times during three 
months in the course of experimental work. She reports that only about 
one out of ten lice produces a sensation like the prick of a fine needle 
when biting; itching only supervened when about 34 young larvae were 
