Researches on Insect Flagellates introduced into Vertebrates. 141 
also on the 6th day, and leishmaniform elements on the 18th day 
after inoculation. Nineteen days after the commencement of the 
experiment, the lizard died. During the last week of its life, 
it did not feed so well as its control. At autopsy the organs 
appeared to be normal, except for a slight softening of the liver. 
Preparations, however, showed that the liver, heart and bone- 
marrow contained leishmaniform and elongating parasites, while 
in the spleen, fully formed flagellates, presenting the typical 
Crithidia facies, occurred. Smears of the lung and kidney were 
negative. The presence of dividing forms showed conclusively 
that Crithidia gerridis can not only maintain itself, but can also 
perpetuate its race in a vertebrate host. 
Experiment 9 (H.B.F.). A second male lizard was fed with 
teased portions of the liver of the first one, which was infected 
with Crithidia gerridis. After four days the lizard refused to 
feed and died on the sixth day. At autopsy, parasites were found 
in the internal organs, their appearance and distribution being 
like those of the “seed” animal. 
Experiment 10 (H.B.F.). A third female lizard has been 
inoculated intraperitoneally with heart blood from the preceding 
animal, and has already shown a few leishmaniform parasites. 
Three passages of the parasite have thus been accomplished. 
Experiment 11 (A.P.). A male grass-snake, Tropidonotus natria, 
was fed with the guts of four Nepa cinerea, poorly infected with 
Herpetomonas jaculum, a few flagellates and preflagellates only 
being present. Blood examinations were made daily. On the 
4th, 10th, 13th and 19th days after feeding the blood showed 
oval, leishmaniform parasites, mostly free. On the 7th and 15th 
days non-flagellate dividing forms were present, as well as leish- 
maniform bodies. Hlongating parasites were seen on the 11th 
day. On the 8th day after feeding a single erythrocyte was found 
containing a small uninucleate parasite, perhaps corresponding to 
the forms described by Laveran and Franchini. 
The snake died 20 days after the experiment began. Smears 
of the organs were made. The liver contained well formed herpe- 
tomonad flagellates and some leishmaniform parasites. The spleen 
harboured a few small flagellates. Dividing non-flagellate forms, 
as well as ovoid parasites, were present in the kidney. Leishmani- 
form bodies were found in the lungs. Smears of the spinal cord near 
the middle of the body showed the presence of non-flagellate forms, 
both ovoid and in process of division. 
(d) EKaperiments with Mammalia. 
Kaperiment 12 (H.B.F.). A young male mouse, Mus musculus, 
weighing 49 grams, was fed with the rectal end of the 
gut of a larva of Stratiomyia chameleon. The gut contained 
