. 138 



and immunising doses of quinine during the first half of the summer, 

 proven carriers receiving intensive treatment. Systematic inspections 

 were conducted at least once in each week to determine the taking 

 or failure to take c[uinine as recommended, the efficacy of the screening 

 and the incidence of illness and its nature. At intervals of two weeks 

 a mosquito survey of all premises was made to ascertain the variation 

 in Anopheline incidence ; and detailed explanations of the various 

 operations and their purpose were made to all adults concerned, 

 supplementary illustrated lectures being delivered during the early 

 summer. 



As a general result malaria has been markedly less on the controlled 

 plantations than in adjacent areas where no prophylactic measures 

 were in use. By the screening method a reduction in malaria of 

 70 "6 per cent, was obtained in group A, the cost per head of screening 

 being about seven shillings ; the administration of immunising doses 

 of cjuinine effected a malaria reduction of 64 '45 per cent, at a cost 

 per head of rather more than two shillings ; and of the carriers to 

 whom sterilisation doses of quinine were administered, only 3 remained 

 infected, being a reduction in malaria of 95"17 per cent. 



Leishman (Col. Sir W. B.). A Note on the Granule-Clumps found in 

 Ornithodorus mouhata and their Relation to the Spirochaetes of 

 African Relapsing Fever (Tick Fever). — Ann. Inst. Pasteur, Paris, 

 xxxii, no, 2, February 1918, pp. 49-59. [Received 6th May 1918.] 



Previously published papers by this author record the study of 

 tick fever in monkeys and mice, induced by the bite of Ornithodorus 

 moubata, the fever being associated with the occurrence of large 

 numbers of Sjnrochaeta duttoni in the blood. Special points dealt 

 with were : — The fate of spirochaetes ingested by the ticks, the nature 

 of the hereditary transmission of the infection in the tick and the 

 mechanism of infection by the bite of the tick [see also this Review, 

 Ser. B, i, pp. 33 & 215]. The present note records recent observations 

 which go to prove that some, at all events, of the granule clumps 

 almost constantly found in various tissues of Ornithodorus, and in the 

 eggs of the fecundated female tick, are derived from spirochaetes, 

 and are able subsequently to develop again into spirochaete form ; 

 these clumps therefore represent a stage in the cycle of development 

 of S. duttoni in the tick. 



It is found that the spirochaetes, after ingestion by the tick, retain 

 their motility for several days, the period depencUng chiefly on the 

 temperature at which the ticks have been kept ; but subsequently 

 they lose their motility and tend to agglomerate into large tangles 

 or masses. Others, however, behave differently and develop a lateral 

 or terminal bud, which later separates and corresponds to an isolated 

 granule clump. Later, there occurs a period of a few days during 

 which either no spirochaetes at all can be detected, or only very rare 

 ones that are seldom motile. Next, especially in ticks that have 

 been kept at comparatively high temperatures, there appears a sudden 

 re-invasion of the tissues with numerous and vigorously motile spiro- 

 chaetes, often very dift'erent in size and general appearance from those 

 which were originally ingested by the tick. 



