G. H. F. Nuttall 
185 
shirts on ant hills. I have seen a similar statement relating to British 
troops in the Boer war. 
(b) Parasites. 
As far as I am aware, only one species of parasite has so far been 
found in the louse apart from Spirochaeta recurrent is and the undeter¬ 
mined causative agent of typhus fever. Mackie (1907, p. 1706) 
casually mentions having found “ Crithidia ” in body-lice and this 
doubtless gave the clue to Fantham (1912, pp. 505-517) who found 
the parasite he named Herpetomonas pediculi in 25 out of 300 lice he 
examined. The protozoon occurs in the gut and faeces of the insects 
where it is stated to form cysts, which, escaping with the louse’s faeces 
upon the human skin, serve to infect other lice that feed upon the 
contaminated spot on the host'. 
Acknowledgments. I am especially indebted to Mr Charles Harpley, 
my Laboratory Assistant, for his willing help, given at the cost of much 
personal discomfort, in connection with these investigations. My thanks 
are also due to Dr W. H. Hamer, Mr A. Bacot, and to Captain Harold 
Orr of the Canadian Army Medical Corps, for kindly supplying strains 
of body-lice and head-lice with which some of the observations here 
recorded were carried out. 
REFERENCES. 
See Bibliography, pp. 1 et seq. 
