376 
Patholo(jlc(d effects of Plitliirus 
The itching may however be moderate or totally absent, but, as Payne 
(1890, p. 209) points out, the lack of reaction may he individual. 
Dubreuilh and Beille (1895, p. 135) relate that some heavily infested 
persons do not even show unconsciously inflicted scratches upon their 
skin, and Lailler, whom they cite, states that pruritus often begins 
only from the moment that the individual recognizes he is lousy, after 
which he may go on scratching himself subsequent to the removal of 
the parasites. Therefore, although the itching is primarily attributed 
to the toxic saliva of the louse it may be partly self-induced. 
A remarkable case of long continued tolerance of crab-lice on the 
person is that described by Hewetson (1894, p. 19), to which reference 
will again be made, wherein an Austrian soldier intentionally remained 
parasitized for ten years. It is evident that the insects put the soldier 
to little inconvenience for he protested against their removal. 
Apart from the discoloration of the skin that is commonly induced 
by the crab-louse and which will be presently referred to, the secondary 
inflammation is usually slight (Osier, 1892, p. 15), although there may 
he 'pajmlar eruptions complicated by eczematous inflanmiation (Morris, 
1911, p. 556). These effects, as Dubreuilh and Beille (1895, p. 135) 
point out, are chiefly due to eruptions following scratching, the papules 
having their tops scratched off, the eczema, etc., being localized in the 
pubic and axillary regions. In a soldier suffering from a heavy generalized 
infestation, whom I had under observation in the summer of 1915, 
besides numerous excoriations on the trunk and limbs, there was severe 
eczematous inflammation present in both axillae where hundreds of 
Phthirus were found, the hair being glued together by partly inspissated 
secretion, the armpits and shirt beneath being bloody from continual 
scratching. Where, as in Hilgenberg’s (1854, vide Bibliography, p. 20) 
and also Fischer’s case (see p. 387) crab-lice are present on the upper 
eye-lids, they may cause considerable irritation, whilst Dubreuilh and 
Beille (loc. cit) state that the lice may cause blepharitis of the ciliary 
borders of the lids with a variable amount of pruritus. 
Fever, headache, etc., attributable to no other cause according to 
Payne (1890, p. 209), may perhaps be due to the toxic action of Phthirus^. 
It is conceivable that crab-lice may cause a rise in body temperature 
like that Payne has seen occur after mosquito bites; a similar case has 
^ As bearing on this matter, I append a note by way of an addendum to what is stated 
on p. 78 regarding P. humanus producing fever by its bites. Jamieson (1888, p. 321) 
records two cases in which body-lice caused fever: (1) girl of 14 years, severe pruritus, 
covered with lice; temperature fell from 103° F. at once when she was freed from parasites. 
