W. S. Patton 
127 
life histories as the human parasite does in man, and in the bed bug 
Cimex rotundatus. We therefore see no reason why this flagellate should 
be placed in a distinct genus (see also remarks in recent paper by Patton, 
1909). 
Woodcock makes no reference to Nicolle’s (1908—1909) recent work 
on Herpetomonas infantum, the causal agent of Algerian herpetomoniasis. 
Nicolle has studied ten cases of this disease in Tunis, the characteristic 
symptoms of which are, irregular fever, anaemia, general emaciation, 
hypertrophy of the spleen and oedema. All the cases occurred in young 
children from several months to five years old ; Indian herpetomoniasis 
on the other hand is common both in children and adults of all ages. 
Nicolle has only been able to find the parasite once in the peripheral 
blood of a patient; this contrasts markedly with Donovan’s observations 
in Madras, where Kala-Azar is diagnosed solely by examinations of the 
peripheral blood. Nicolle (1908—1909) has succeeded in reproducing the 
Algerian disease in dogs and monkeys, by inoculating them with infected 
tissue ; he has also cultivated the parasite on blood agar, not only from 
the spleens of diseased children, but also from naturally infected dogs. 
He however failed to reproduce the disease in dogs and monkeys by 
inoculating them with pure cultures, and concluded that the cultural 
forms had probably lost their pathogenicity. Novy (1909) has however 
recently succeeded in infecting a dog with H. infantum by inoculating 
it with 270 tubes of blood agar cultures in 15 inoculations extended over 
a period of 161 days. We would like here to draw attention to a point 
which we think both Nicolle and Novy have overlooked. It is well 
known that in artificial cultures of these human parasites many of them 
never develop into flagellates, but some remain for many days, even 
months, unchanged; we have ourselves seen this in cultures of the para¬ 
site of Kala-Azar. Now Nicolle and Novy’s observations show that a 
very large number of cultural forms (flagellates) have to be inoculated 
before the disease can be reproduced in dogs, whereas a small quantity of 
blood containing the undeveloped parasites readily produces it. Could 
it not then be that in Novy’s cultures there were some unchanged (our 
pre-flagellate stage) parasites, and that by inoculating a sufficient number 
of these he was able to reproduce the disease ? Novy however does not 
state whether his cultures contained unchanged forms in addition to the 
flagellates ; we would draw his attention to this point. The reason why 
we suggest this, is because we have demonstrated beyond any doubt that 
all Herpetomonads, in order to pass from one host to another, must 
return to their non-flagellate (post-flagellate) stages. In the case of 
