ON KALA-AZAR 141
rotundatus), suggesting that it may be a true parasite of the bug' and have no connection with the human parasite. This criticism was quite justifiable, and he (Captain Patton) had paid special attention to this possi- bility. When carrying out his feeding experiments in Madras, he obtained a collection of bugs from almost every large town in India, as well as from Mauritius, North and South Africa, and China ; the majority of the insects were alive when they arrived. He had dissected a large number of these bugs in order to find out whether they had a natural parasite of their own, but he was unable to find any. He had recently inoculated dogs with H. donovani in the same way as Nicolle; after keeping the dogs for two months they were killed, and on examining their organs he was unable to find a single kala-azar parasite. So far as he was able to ascertain, dogs in Madras did not harbour this parasite.
