146 Drs Fantham and Porter, Further Experimental 
when in Senegambia, found a Herpetomonas in the blood of house 
mice. From the description given, there can be no doubt that the - 
organisms actually were herpetomonads. We have also found | 
herpetomonads occurring naturally in mice in England, and are | 
publishing a paper on the same in Parasitology. (See list of 
References. ) 
As we have previously stated, we believe that leishmaniases | 
are insect-, or rather, arthropod-borne herpetomoniases. It is | 
highly probable that the maladies have originated from the intro- | 
duction of flagellates of invertebrates—especially herpetomonads | 
of insects—into vertebrate hosts, in which they have been able to | 
establish and propagate themselves. | 
Preventive measures in areas where leishmaniases are endemic | 
should be directed against invertebrates harbouring herpetomonad — 
flagellates, especially such invertebrates as may come in contact 
with men and dogs, and even with domestic vermin like rats and — 
mice. Arthropods need special attention in this connection. It 
is likely that certain vertebrates, such as reptiles and amphibia— 
especially those that are insectivorous—may serve as reservoirs of 
leishmaniases (herpetomoniases). rom such reservoirs the herpe- 
tomonads may reach man by the agency of ectoparasites or flies, 
especially such as are sanguivorous. 
VI. Summary. 
1. Herpetomoniasis can be induced in various warm- and | 
cold-blooded vertebrates when the latter are moculated or fed with 
herpetomonads occurring in the digestive tracts of various insects. 
The infection produced and thé protozoal parasites found in the 
vertebrates resemble those of human and canine leishmaniases. 
2. An infection can also be induced in certain vertebrates 
when they are fed or inoculated with Crithidia gerridis, and both 
flagellate and non-flagellate stages occur therein, but no transition 
to a trypanosome was found. 
3. The following Flagellata have proved pathogenic to warm- 
blooded mammals when the latter have been fed, or imoculated 
subcutaneously or intraperitoneally with them—Herpetomonas 
jaculum, H. stratiomyiae, H. pediculi and Crithidia gerridis. The 
hosts used were mice of various ages. That H. ctenocephali can 
infect dogs has already been shown by us. 
4. Herpetomonas jaculum and Crithidia gerridis have also 
been successfully fed or inoculated into cold-blooded hosts, namely, 
fishes (Gasterosteus aculeatus), frogs, toads, lizards (Lacerta vwipara) 
and grass-snakes (T’ropidonotus natria). 
5. As we have previously stated, we believe that leishmaniases 
