(t. H. F. Nuttall 
207 
Those who regarded whites and negroes as belonging to different species, 
concluded that the lice found on them were also of different species because 
of their difference in colour. Murray, like others before him, found that lice 
taken from negroes were dark whilst those-from whites were pale. He remarks 
that colour is of little value in differentiating species because it “may be 
derived from the nature of the feeding ground,'' some observers stating indeed 
that the negro’s lice grow pale when transferred to whites and vice versa. The 
Rev. Hislop, “known as well for his scientific as for his missionary labours in 
India,” informed Murray, “ that at Nagpore he thinks he has seen dark Pediculi 
which have found their way from coloured nurses to white children, after a 
time becoming white,” and another friend told him that “when seated in 
church behind two lads—the one dark-haired and the other light-coloured, 
both swarming with vermin—he noticed that those upon the dark-haired lad 
were darker than those upon the light-haired one.” 
That Phthirus pubis is likewise capable of changing its colour is indi¬ 
cated by Mr G. E. Bodkin (Government Economic Biologist, Science and 
Agriculture Department, Georgetown, Demerara), who, in a letter addressed 
to me (8. iv. 1918), states that the insect is very common in Demerara and 
that he “can speak from personal experience with regard to the chameleon- 
like qualities of these creatures; when transferred from a negro (where of 
course they exactly match the colour of the skin) to a white person, they will, 
in the course of a few generations become almost transparent and extremely 
difficult to see so closely do they resemble the white skin to which they are 
attached.” 
Whereas all specimens of Phthirus pubis collected from whites and ex¬ 
amined by me have been f mnd to be pale or slightly pigmented, those found 
on Suaheli negroes (N. 284 from Zanzibar, sent by W. Mansfield-Aders, and 
other lots) are deeply pigmented in the heavily chitinized regions, the whole 
integument being dusky. 
The accuracy of Murray's statement regarding the variation in colour 
shown by lice on different races of man has been doubted by several authors. 
Schjodte (1864) noted the great variability in the colour of lice and so did 
Neumann (1910), the latter, however, records the presence of dark head-lice 
on negroes. Piaget (1880, p. 622) collected body-lice in Holland and saw great 
differences in the coloration of the specimens; he compared lice from Malaya 
and Europe and found them alike. Blanchard (1890, p. 437) refers to Murray 
and agrees with him in regarding the colour differences as devoid of specific 
significance, he nevertheless cites F. A. Pouchet (no reference; probably 1832 
1841) as considering lice from negroes and whites distinct species. 
Although not referring to Murray, Sikora (viii. 1915, p. 533) notes that 
variation in colour can be observed in lice taken from one person, three types, 
white, medium and dark being distinguishable to the naked eye. Peacock 
(1916, p. 32) examined 1800 lice (source and stages not stated) and found 
5-4 per cent, to be “black,” 
Parasitology xi 
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