21 
unsuccessful, although they repeatedly introduced into one rat blood 
rich in parasites and nourished one rat chiefly by this material. They 
placed together an infected tame rat and a noninfected wild rat, and 
state that after a hot combat the tame one was killed by the wild, rat 
and eaten with much pleasure. Parasites appeared in his blood after 
ten days. They did not regard this as a case of infection necessarily by 
the digestive tract, as the parasites may have entered by the numerous 
bites and wounds, nor do we regard it as such ; but we think we have 
in our experiments removed the likelihood of entrance through wounds 
and have established the existence of infection through the digestive 
tract alone. 
5. Transmission by fleas . — Rabinowitsch and Kempner, with a view 
to finding the natural mode of transmission, placed together an infected 
white rat with a healthy white rat. The latter became infected in 
eleven days. They repeated the exj)eriment and found parasites in 
the blood of another rat after fifteen days. A gra}^ rat showed para- 
sites in his blood after fifteen days’ confinement with tAvo infected 
animals. The three rats which became infected had manj^ fleas on 
them. Examination of a great number of teased preparations of the 
fleas did not reveal any of the trypanosomes in them. They then 
mashed up fleas collected from infected rats and injected this material 
into the peritoneal cavity of nine AA^hite rats. FiA^e became infected. 
Likewise four rats were injected intraperitoneally with mashed-np lice, 
but no infection followed. The next experiment AA^as to determine 
whether the bites of fleas Avere infecthx. Twent}^ fleas were collected 
from infected rats and placed on one healthy white rat, which after three 
weeks time Avas found to be infected Avith trypanosomes. They say 
that from this one positive experiment they conclude that fleas can carry 
trypanosomes, and in the absence of j)roof of another Avay of com^eyance 
they are of the opinion that fleas are the ordinary medium of infection. 
Jourgens states that his experiments were not then complete, but 
that he had kept infected rats and healthy rats together in the same 
cage without infection taking place, although the animals Avere 
strongly beset with fleas, while a later inoculation of the sound ani- 
mals proved them to be susceptible. 
6. Trypanosomes in lice . — LaA^eran and Mesnil found trypanosomes 
in the stomachs of lice Avhich infested infected rats, but do not report 
a conveyance of the disease by lice bites. 
7. Trypanosomes in Stegomyia fasciaia. — We may be pardoned for 
mentioning a subject which is entirely outside of rat trypanosomes — 
but it may ha\"e some future bearing on the disease — to state that 
within a year Durham (10) has reported finding tiypanosomes in a 
mosquito, thus adding one more to the rapidly growing list of diseases 
through which this little creature threatens the i3ublic health. Dur- 
ham’s report is inserted. 
A small bat (Phyllostoma) which could not be examined at once was placed in 
a gauze cage, and Avith it a specimen of Stegomyia faseiata. The next day the bat 
