NOTES 137 



hundreds of kinds of mosquitoes, and it does not follow at all that the 

 malaria-bearing species is most prevalent even in the most malarious spots, 

 while, at the same time, the task of determining the development of these 

 minute unicellular parasites in mosquitoes was far more difficult than that 

 of tracing the development of large worms in the same or in other insects. 

 This work occupied me for four years of severe labour, chiefly owing to 

 official interruptions of my work on three occasions. I first found the human 

 malaria parasites gro\\'ing in the Anopheles mosquito on August 20, 1897, 

 and could have proved the whole life-cycle then but for an interruption of 

 five months. My researches were communicated to Manson in a series 

 of 1 10 letters, and were published in of&cial reports and in the British Medical 

 Journal by him and by me. My work was bitterly opposed just as Manson's 

 work on Filarics hancrofti had been, and was not generally accepted until 

 it had been pirated by certain Italian writers in 1898-9. By that time I 

 had infected numbers of healthy birds by bites of mosquitoes, and the 

 Italians subsequently claimed to have infected three men in Rome in a similar 

 manner ; while the life-history of the Plasmodiutn in mosquitoes had been fully 

 worked out by me and then by the Italians. In my paper on the Cultivation 

 of Proteosoma in Grey Mosquitoes (1898) I gave Manson the full credit of my 

 work up to that time, especially because he was then being violently attacked 

 in the Medical Press for another matter. 



Unfortunately, however, Manson's conjectures were sound only up 

 to the point mentioned above, that some suctorial insect carries the Plas- 

 modium. After that he plunged into a hypothesis which was quite erroneous, 

 which led me wrong, which I was soon obUged to abandon, and which was 

 finally disproved by MacCallum in 1897. Here again, as so often before, 

 the working hypothesis proved to be nothing but a clue wliich frequently 

 breaks in the hand ; and, though the medical profession does not easily 

 understand the difference, a conjecture, however plausible, is very far indeed 

 from an established theory. I have always been surprised that Manson 

 made no attempt to work out his own h^^pothesis for himself at the Royal 

 Albert Docks in London, where he had as much material, both malaria cases 

 and mosquitoes, as I often possessed in India. I urged him at least twice 

 to do so ; and before I left London in 1895 begged him to use malaria- 

 infected birds for the purpose. He gave or procured for me little informa- 

 tion about mosquitoes and his technique for Filaria hancrofti was much 

 too coarse for the delicate malaria work. The whole life-cycle of the Plas- 

 modia in mosquitoes was estabhshed by me before August 1898 — the first 

 case of metaxeny in Protozoa. I returned to England in February 1899, 

 and spent much of the succeeding years in visits to Africa, Ismaiha, Panama, 

 Greece, Mauritius, and Cyprus in order to perfect and stimulate malaria- 

 reduction by the methods of mosquito-reduction first fully described by me 

 in 1899 [British Medical Journal). 



In 1898, largely in consequence of my malaria work, Manson persuaded 

 Mr. Joseph Chamberlain, then Secretary of State for the Colonies, to recom- 

 mend the estabhshment of Schools of Tropical Medicine. They should really 

 have founded a Colonial Of&ce School on the model of the Netley School 

 of the War Office and India Office ; but, instead of that found it cheaper 

 to get the thing done by voluntary subscriptions. This of course meant 

 that the teachers were the sufferers, as I myself can testify from my experi- 

 ences at Liverpool — small salaries and no pensions. But it was a good 

 stroke of business on the part of the Colonial Office, wliich not only got its 

 doctors taught the elements of tropical medicine for almost nothing at 

 our expense, but obtained numerous malaria surveys and scientific expedi- 

 tions to Africa and elsewhere for as little expenditure. Small gratitude 

 has it shown for the work. Manson's school in London was chiefly a teaching 

 centre ; but we in Liverpool made most of the surveys and certainly in- 



