Gr. H. F. Nutt ALL 
385 
infestation occurring from man to man, as has frequently been observed 
in barracks, soldiers may very frequently become infested. Lieut. A. D. 
Peacock, K.A.M.C. (Ms. Eeport, i. 1918), among soldiers selected at 
random, found two out of thirty men of the R.F.A., and one out of 
twenty-five men of the R.A.M.C. to be infested with crab-lice. The 
occurrence of the parasites on old people and children is relatively rare. 
Occurrence on other Hosts than Man. 
To my knowledge Phthiriis has not hitherto been reported as having 
been found on another host than man. I have two instances to record 
of its presence on the dog (see under geographical distribution, p. 384). 
In one case ten adults were collected from the axilla of a dog by Mr S. A. 
Neave on an expedition undertaken for the Imperial Bureau of Entomo¬ 
logy. The number of parasites present in this situation on the dog 
renders it evident that the insect had found a fairly suitable habitat. 
The second case is that supplied by Mr C. B. Williams of the Agricultural 
Department, Trinidad, W.I., who kindly sent me a mounted specimen 
that had been found on a dog at Boc’as del Toro, Panama. It would be 
of interest to determine if Phthirus can be raised experimentally upon 
the dog. 
The Distribution of Phthirus on Man’s Body. 
The parasite is usually confined to the f iibis and peri-anal region as 
common experience shows. It may, however, spread upward on the 
abdomen and breast and down the thighs, or it may become disseminated 
practically all over the body. Its spread is doubtless facilitated by 
scratching which may be unconscious or the reverse. Occasionally in 
young children, rarely in adults, the louse may be found localized upon 
the head, especially upon the eyelashes, eyebrows, more rarely on, the 
scalp and then only along the margins of the hairy parts and occasionally 
in the beard. Linnaeus (1761, p. 475) states of crab-lice “Habitat in 
hominum immundorum pube et cihis,” and Fabricius (1775, p. 805) 
writes “Hospitatur in hominis immundi pube, rarius in superciliis.” 
I append some case records culled from various sources: 
Cases of General infestation in adults. 
Woman, aged 23, active stages and nits present on the hair of the 
head about the occiput and on the temples, in the axillae and on the 
pubis (Waldeyer, 1900, pp. 494-9). 
