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A Critical Review , etc. 
on infected blood ( T. brucei), Stuhlmann considers the above cycle 
represents the development of Trypanosoma brucei. It is, however, 
important to note that he was unable to infect animals with any of the 
forms he describes. Before criticising Stuhlmann’s work it will be 
necessary to refer to two flagellates one of us has recently studied in 
Madras. 
When endeavouring to follow the vermicides of Leucocytozoon leporis 
in the tick, Haemaphysalis flava, from Lepus nigricollis, the pre-flagellate 
stage of a flagellate was found in the gut diverticula of the larval tick; 
these forms corresponded exactly with similar stages of Crithidia gerridis, 
Herpetomonas donovani and II. lygaei. In fed larvae, kept for a few days, 
further development of these forms was observed, viz. the development 
of the flagellum, multiplication and formation of adult Crithidia 
and in the nymphs these flagellates were found in abundance. It 
was also discovered that only a certain percentage of the larvae from 
one adult was infected. Naturally the question immediately arose 
where had these flagellates come from ? At first the only reply 
was, from the blood of the hare. Forty-two of these animals were 
examined when studying L. leporis and the blood of two on which a 
very large number of larvae was fed were frequently examined for 
months, both in the fresh and in the stained conditions, and, although 
many of the larvae had flagellates, no such parasites were ever seen in 
the blood of the hares. We are aware that a trypanosome (T. cunicidi ) 
has been found by Jolyet and de Nabias (1891), Nicolle, Petrie (1904), 
Bose (1904), and Bettencourt and Frain^a (1906), in Lepus cuniculus, and 
also that it is quite an easy matter to miss these parasites in the peri¬ 
pheral blood of animals. Yet, in spite of these facts, we believe that 
the flagellate found in the tick is in no way connected with a vertebrate 
trypanosome; the final proof of this will be dealt with elsewhere. Many 
hundreds of recently fed larvae of Haemaphysalis flava were examined, 
but we never found a trypanosome in any of them. As a result of these 
observations it was concluded that this Crithidia of H. flava is trans¬ 
mitted hereditarily. Swingle has informed one of us that he has 
worked out the mode of infection in the case of Crithidia melophagia ; 
he finds that it is also transmitted hereditarily, thus confirming our 
observations on the hereditary transmission of Crithidia. 
The other flagellate referred to above is found in the crop diverticula 
of a species of Glossiphonia sp. ? parasitic on Rana tigrina in Madras. 
In addition to a number of haemogregarines, this frog is infected with 
two species of trypanosomes. After a long series of feeding experiments 
