C. A. Hoare 
75 
fly ( Calliphora sp.), and Crithidia melophagia from the sheep-ked (Melophagns 
ovinus). The animals experimented upon were mice, sticklebacks (Gasterosteus 
acideatus), newts (Molge vulgaris) and frogs (Rana temporaria). 
A. Experiments with Mice. 
All the mice were inoculated intraperitoneally with the contents of the gut 
of insects infected with flagellates diluted with a physiological solution of 
sodium chloride. The animals were sacrificed after varying periods had elapsed, 
their blood being examined regularly till their death. After the animal was 
killed, cultures from its blood and organs—spleen and liver usually—in the 
NNN medium, and stained smears of the blood, peritoneal fluid, liver, spleen 
and, sometimes, bone-marrow and lungs were made. The blood and peritoneal 
fluid were also usually examined in the fresh condition. 
I. Mice inoculated with C. melophagia. 
Experiment 1. Mouse inoculated on October 19th, blood examined for two days with 
negative results. Sacrificed on October 21st. Stained smears of blood, peritoneal exudate, 
fiver and spleen showed no parasites. Cultures made from the heart-blood, fiver and spleen 
kept at 30° C. showed no parasites for 40 days. 
Experiment 2. Mouse inoculated on October 19th. Blood examined with negative results 
till October 25th, when the animal was sacrificed. Stained smears (as preceding) showed no 
parasites. Cultures (as preceding) remained sterile for 36 days. 
Experiment 3. Mouse inoculated on October 19th. Blood examined with negative results 
till October 29th, when the animal was sacrificed. Stained smears and cultures (as preceding) 
negative. Cultures examined for 32 days. 
In experiments 1, 2 and 3 the three mice were inoculated with the contents of five “ked” 
guts; their condition was normal till death. The peritoneal fluid when examined showed 
numerous leucocytes. 
Experiment 4. Mouse inoculated on July 15th. Blood examination during 25 days 
negative. Sacrificed August 9th. Stained smears of heart, blood, livei and spleen showed no 
parasites. Cultures from the blood and these organs kept at 24° C. remained sterile (27 days). 
Experiment 5. Mouse inoculated on July 15th. Blood examination for 35 days negative. 
Sacrificed on August 19th. Stained smears and cultures (17 days) as in the preceding case— 
negative. 
II. Mice inoculated with H. calliphorae. 
Experiment 6. Mouse inoculated on August 9th. Sacrificed next day. Stained smears of 
blood, fiver, spleen, kidney, bone-marrow, lung and peritoneal fluid were negative. Cultures 
from blood kept at 24° C. remained sterile (56 days). 
Experiment 7. Mouse inoculated on August 9th. Sacrificed on the 19th. Stained smears 
(as preceding)—negative. Spleen culture showed no flagellates for eight days, when it 
became contaminated with bacteria. 
In experiments 6 and 7 the peritoneal fluid showed numerous leucocytes. 
III. Mice inoculated with H. jaculum. 
Experiments 8 and 9. Two young mice inoculated on September 15th. Died next day. 
Peritoneal fluid and blood contained numerous bacteria. Blood cultures also showed 
bacteria. 
