84 
Biology of Pediculus humanus 
Figures from Germany are supplied by Kisskalt (13. v. 1915, p. 579), 
who records the monthly returns for January-December 1914, of the 
number of persons whose clothing required de-lousing 1 in the night 
refuges of Berlin. The refuges are under the direction of the Berliner 
Asylverein fur Obdachslose, and between 13,000 and 15,000 persons 
pass through the institutions per month; the refuges are well organized 
and had steam-sterilizers working regularly every night to destroy 
vermin when I visited them some twenty years ago. The proportion 
of admitted persons whose clothes had to be de-loused in 1914, according 
to Kisskalt, varied between 5-2 and 8-0 %; no seasonal incidence of 
pediculosis was observed, there being, for instance, 8 % in August and 
7-3 % in January. 
The Relative Frequency of Infestation with Different Lice. 
That capitis occurs more frequently on females than on males, 
and that the reverse holds to a certain extent for corporis, is shown by 
the figures of Greenough (1888, cited by Blanchard, 1890, p. 445), who 
classified 864 verminous patients admitted to hospital in Boston, 
Massachusetts: 
Capitis was found in 81 men and 419 women; i.e. 500 times 
Corporis „ 
„ 196 
99 
141 „ 
„ 337 
Ph. pubis „ 
„ 26 
99 
1 „ 
„ 27 
Totals 
303 
561 
864 
The Greater Prevalence of Capitis in Children and Old People. 
Children. Head-lice are particularly prevalent in children of school 
age, girls, because of their possessing long hair, being much more fre¬ 
quently infested than boys. 
In England, for instance, Raven (1907, p. 64) records the presence 
of capitis on 80 % of the girls arriving at a convalescent home at Broad- 
stairs, whilst an Editorial (1909, p. 1427) states that at Willesden, 
Lower Place Council School, 60 % of the girls required treatment for 
head-lice. 
Similar conditions are recorded from the United States ; thus Greene 
(1898, p. 70) writes of a school in Boston, Massachusetts, visited by 
756 children, aged 6-16 years, of which about 50 were boys. Only 
200 of the children were free from nits, the remaining 74 % were in- 
1 The word “de-lousing” requires no apology; it was needed as a specific term in this 
war and it has come to stay. The French equivalent is cUpon illage, the German Entlausung 
