434 FAMILY: TRYPANOSOMID^ 



(1920), that the blood of the gecko {Tarentola mauritanica) harboured a 

 flagellate of the leptomonas type, which was only demonstrable by culture 

 of the heart blood. This gave rise to the view, first enunciated by the 

 original discoverers of this organism, that the gecko, on which sand 

 flies were known to feed, probably acted as a reservoir for the virus of 

 oriental sore. Nicolle, Blanc, and Langeron (1920), by careful examina- 

 tion of the cultural forms of the gecko flagellate, concluded that they were 

 distinguishable from the cultural forms of L. tropica. Moreover, injection 

 of cultures of the gecko flagellate into the skin of man and monkeys failed 

 to give rise to oriental sore. They conclude, with ample justification, 

 that there is no real evidence that the gecko flagellate has any connection 

 with L. tropica. 



Strong (1924) has produced in the monkey a lesion resembling oriental 

 sore in which leishmania occurred by subcutaneous inoculation of the skin 

 with a flagellate of the leptomonas type, which occurs in the intestine of 

 the lizard, Cnemidophorus lemniscatus, of Central America, where cutaneous 

 leishmaniasis is endemic. The lizard, it is assumed, acquires its infection 

 by feeding on plant bugs, which in their turn obtain the flagellates from 

 the juices of Euphorbias (pp. 383, 442). Further investigations will be 

 required before it can be accepted that the flagellate in this lesion is 

 identical with that causing the naturally occurring human disease, or that 

 the sequence of events described by Strong has any setiological significance 

 in connection with the natural method of its transmission. 



It has been shown that L. tropica will develop in the bed bug like 

 L. donovani, but there appears to be little reason for suspecting it to be a 

 vector of oriental sore. Lloyd (1924) has found a typical Leptomonas in 

 the proboscis and intestine of Glossina morsitans in Nigeria. As this fly 

 feeds only on blood, it would appear that the flagellate must have been 

 derived from the blood of some animal or man. As human leishmaniasis 

 occurs in Nigeria, the flagellate of the tsetse fly may represent a Leishmania. 



Experiments on the possibility of L. tropica developing in insects have 

 been made by several observers. 



Bugs. — Tlie writer (1911«) observed that when the bed bug fed on an oriental 

 sore before ulceration had set in, it took up leishmania, and a development similar to 

 that described previously by Patton for L. donovani, took place. Pattou (1912) 

 published a more extensive series of experiments with bed bugs, and obtained 

 resiilts similar to those he had obtained with the parasite of kala azar. Working 

 later in England, the writer (1912c) again found that L. tropica developed into 

 flagellates in the bed bug. In no cases did active multiplication occur such as 

 would be expected in the true invertebrate host, and, as with L. donovani, it appeared 

 that the blood in the stomach of the bug had acted merely as a culture medium. 



By a series of ingenious arguments similar to those employed in support of his 

 claim of the transmission of kala azar by bed bugs, Patton attempted to prove 

 that this insect also transmitted oriental sore. The bed bug was supposed to bite 



