HiEMATOZOA OF VERTEBRATES. 
81 
species of Trypanosoma in the domestic pigeon in India and in 
the Indian crow. The domestic pigeon was also found to be 
affected with the hsemamceba, Halteridium danilewskyi (see 
below), but it is not quite clear whether the two parasites were 
present in one and the same host. 
We have not yet come upon Try pa,nosoma in Ceylon elsewhere 
than in the rats of Colombo. 
Trypanosoma lewisi is apparently a non-pathogenic parasite, 
its presence in millions in the blood not affecting the health of 
the host. It has been shown that this species has become split 
up into two physiologically different races indistinguishable mor¬ 
phologically, namely, the parasites of rats and the parasites of 
the Hamster ( Gricetus frumentarius.). Although these parasites 
are identical in form and properties, yet an inoculation of the one 
parasite into the host of the other never takes effect.* 
It appears that Koch (1898) was the first to demonstrate that 
the Trypanosoma of the Nagama disease of cattle, T. brucii , could 
be transmitted by inoculation into rats and other animals, while 
the rat parasites are only transmissible to rats. 
Bradford and Plimmer (Quart. Journ. Micr. Sc. vol. 45, 1902, 
p. 450, &c.), found that sewer rats naturally infected with J\ 
lewisi were not immune against the fatal effects of T. brucii 
when introduced into their blood by inoculation, but that they 
died in the usual time, five days after inoculation. 
Rabinowitsch and Kempner showed that rat-trvpanosome is 
transmissible to white rats by inoculation, but these exhibit 
no tendency to spontaneous infection. The same authors also 
ascertained experimentally that rat-trypanosomes can be trans¬ 
mitted from one host to another by fleas, a discovery which was 
confirmed by Laveran and Mesnil.f 
We may add some brief notes on the action of various chemical 
substances on Trypanosoma lewisi . 
For these experiments a small loopful of trypanosoma-infected 
blood was mixed with the same quantity of the chemical, the 
action of which we wished to test. Hanging drop preparations 
were made, carefully sealed with vaseline. All the experiments 
were performed at the temperature of the room (about 87° 
* v. Wasielewski and Senn. Beitrage znr Kenntniss der Flagellaten des Ratten- 
blutes. Zeitschr. f. Hygiene und Infectionskrankheiten. Bd. 33, 1900, pp. 444- 
472, Taf. VII.—IX., see p. 458. 
f Cf. Lydia Rabinowitsch and W. Kempner, Die Trypanosomen in der Menschen- 
und Tierpathologie, sowievergleichende Trypanosomennntersuehungen. Centralbl. 
Bakt. Parasit. Abth. 1. Bd. 84, 1903, pp. 804-822. This Paper includes a very full 
bibliography of Trypanosomosis. 
8(3)04 M 
