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Insect Flagellates , etc . 
Contents of the gut of the water-scorpion (Nejja cinerea) infected with 
Herpetomonas jaculum were placed at room temperature in saline and in 
slightly alkaline nutritive bouillon. In both cases the flagellates remained 
alive for five days. It was observed that towards the end of that period their 
movements became slower, many had become rounded off, retaining their 
flagella, others had swellings on different parts of their body. 
Regarding the vitality of C. melophagia Flu (1908) mentions that it is 
possible to keep them alive in normal saline only for two hours, and in serum 
for eight hours at room temperature. In an ice chest they remained alive for 
six days. According to Porter (1909) the same flagellates remain alive for 
several hours at room temperature. Georgewitch (1910) kept his flagellates 
living in drops of serum for several days. 
CONCLUSIONS. 
In my experiments on artificial infection of mice with Crithidia melophagia, 
Herpetomonas jaculum and H. calliphorae, I was unable to confirm the results 
obtained by Laveran and his collaborators, having found no traces of infection 
or of the presence of any forms of flagellates in the animals experimented upon. 
Whether this is due to difference in methods or to some other cause, it is 
difficult to tell. The most remarkable feature of the experiments of these 
observers is that positive results were produced so invariably, whereas in my 
experiments made on fifteen mice which were most carefully examined at 
different periods of their life and post mortem , and in all cases tested by cultural 
methods, the results were always negative. This difference cannot be due to 
the authors mentioned having used flagellate cultures for inoculation, as they 
started experimenting with cultures only since 1919; up to that time they 
produced positive results by inoculating flagellates directly from the guts 
of the insects and otherwise. As it is, my experiments, which are not so 
numerous and varied as those discussed, although not disproving the ex¬ 
periments described by Laveran and his collaborators, at any rate clearly 
show, together with the experiments of Wenyon (1908, 1914), Chatton (1919) 
and Noller (1920), that artificial infection with insect flagellates requires 
further study and the results already recorded do not permit as yet of forming 
general conclusions as to the pathogenicity of insect flagellates, and their 
relation to Leishmaniasis. 
In connection with this, I should like to add that in some of the experiments 
discussed the results are difficult to understand. For instance, Franchini and 
Mantovani’s (1915) experiments with H. muscae-domesticae are quite incom¬ 
prehensible. The authors state that blood cultures from a rat inoculated with 
these flagellates produced only “anaplasma" bodies. These bodies, when re¬ 
inoculated into a mouse, gave rise to leishmania forms. The “anaplasma/ 5 as 
we know it, is merely a structureless granule within red cells, which stains red 
with Romanowsky stains, and it is still questionable whether it is in reality 
an organism at all, although some recent workers definitely assert that they 
