158 Crithidia, Herpetomonas, Trypanosoma 
infection. Herpetomonas jaculum, about whose host Dr Woodcock 
apparently has such incorrect views, is also stimulated by vertebrate 
blood to divide. 
The finding of a trypanosome in the blood of a sheep makes no 
difference—at present—to the matter. If Dr Woodcock is so sure that 
the trypanosome he discovered is connected with G. melophagia in the 
sheep ked, let him pr'ove it, not rush into print with “ possibilities,” 
which he further uses to edit the names of parasites described by other- 
investigators, in an International Catalogue. G. melophagia, considered 
as an independent organism long before he knew anything about it, 
must now, according to our worthy, be shown not to be a developing 
Trypanosome. I commend him for his logic. 
In connection with the subject of flagellates of blood-sucking insects, 
perhaps I may be permitted to draw attention to a research of mine 
(about to be published) on Grithidia piulicis, n. sp. from the human flea, 
Pidex irritans. Grithidia, pidicis has the typical life-history, pre-flagellate, 
flagellate and post-flagellate stages are produced, and the method of 
infection is contaminative. The fleas were bred for three generations 
before being dissected, the third generation being used, and the breeding 
was carried out in special “ flea proof” cages of my own design upon my 
own body. There has been no evidence of hereditary infection. There 
is no doubt whatever that I am not a victim of trypanosomiasis, and 
this has been attested by many highly competent workers on human 
trypanosomiasis. Human fleas, obtained from different parts of England, 
and their progeny up to the third generation have been examined and 
G. pulicis found in them. According to Dr Woodcock’s “ generalisation,” 
an enormous number of people in the British Isles—to say nothing of 
Continental nations—must be the unwilling hosts of some hitherto 
unknown trypanosome. Yet though thousands of blood smears have 
been made and examined annually in hospitals and scientific institutes 
and numerous blood cultures are prepared for various medical purposes, 
the occurrence of the vertebrate trypanosome yet remains unrecorded, 
though the unwilling victims of flea bite may number millions. 
However, Dr Woodcock, holding the views he does, will doubtless 
now search for some hitherto undiscovered human trypanosomes, spread 
by blood-suckers such as sheep keds, water boatmen, water scorpions, etc., 
all of which feed greedily on human blood when they get the chance. 
I hope he will take up these researches. Their prosecution at any rate 
will preserve the protozoological world from a few of his wild hypotheses 
for the time being. We have had a surfeit of crude hypotheses and 
