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138 opportunity for working out the life-history of the kala-azar parasite. No one was justified in experimenting with so deadly a parasite as that of kala-azar, but one was justified in experimenting with the parasite of Oriental sore; if experiments with the latter were successful they might throw light on kala-azar. Vigorous efforts should, therefore, be made to work out the life-history of the parasites of Oriental sore.

Captain, in reply, said that, owing to the shortness of his paper, he had been unable to deal with all the points which had been raised in the discussion; he wished, however, to correct some erroneous views. Dr. Sambon had spoken in a very loose way of the sexual forms of these flagellates of insects, but he (Captain Patton) would like to point out that there was not the slightest evidence at present to support the view that they had such stages; the so-called male, female, and indifferent forms merely representing parasites of varying ages which had resulted from equal or unequal longitudinal division of adult parasites. The thin forms which Leishman had described splitting off from the adult flagellates of the parasite of kala-azar were certainly not sexual forms; a large number of these flagellates exhibited this marked polymorphism, and the conjugating forms of some writers were readily explained by the unequal longitudinal division of the adult flagellate.

In going into the history of these so-called developmental forms of vertebrate trypanosomes in invertebrate hosts, it is quite evident that natural flagellates of the invertebrate liosts have been entirely omitted; he (Captain Patton) said that in a paper shortly coming out in the Journal of Parasitology (vol. i., part iv.), he had written a critical review of the whole subject, and would