182 



boracic acid, fusel oil, sinapis oil and aniseed oil at strengths consider- 

 ably below 1 per cent. When sawdust was employed instead of sand, 

 the mortality was considerably decreased, but 46 per cent, of the young 

 and 36 per cent, of the old larvae controls died, mainly, it is supposed, 

 owing to the Chalcid parasite. These experiments tend to show that 

 the high results obtained with sand could not be expected in actua 

 practice on the fleece, owing to the higher absorptive power of the 

 latter. The highly poisonous nature of arsenic sulphide, nitro- 

 benzene and creosote is confirmed by this series of experiments. 



Emulsions were tried as follows : 40 grms. of sawdust were sprayed 

 with a 1 per cent, emulsion of the chemical to be treated until just damp, 

 and 50 larvae were placed in it in a glass jar ; saprol and a mixture 

 of /S-naphthol and sulphur were the only chemicals which gave good 

 results. Vapours were tested by passing air, saturated with the vapour 

 of the chemical, over the larvae for 3| hours. They were then removed 

 and placed in sawdust in glass jars ; mono-bromobenzene, chloral 

 hydrate, pyridine, ethyl acetate and iodine were the most effective. 

 The authors are careful to state that these experiments are only pre- 

 liminary and were made under laboratory conditions, and they regret 

 that properly conducted field work under natural conditions is 

 impossible in England. 



MiTZMAiN (M. B.). Anopheles as a Winter Carrier of Plasmodium; the 

 Mosquito as a Prophylactic Indicator.^ — Public Health Reports, 

 Washington, B.C., xxx, no. 29, 16th July 1915, pp. 2117-2121. 



It seems quite feasible to establish for any endemic focus the period 

 of the year when mosquitos first acquire malarial infection. Thus a 

 fairly stable indicator may be obtained of the time when there is a 

 danger of the communication of malaria from man to man. It should 

 also be possible to utilise this indicator to determine when prophylactic 

 measures should be inaugurated in any locality or when they might 

 be safely dispensed with. A locality which had been proved to have 

 had a malarial index of 40*9 per cent, during September 1914 among 

 1,666 persons examined, was chosen for investigation. The work was 

 done between 3rd February and 1st June 1915, near Scott, Miss. 

 Material was obtained in and about habitations and in the woods 

 and swamps. The first Anophelines were found with the aid of an 

 electric torch, during the month of February, resting under the flooring 

 of dwellings. They were collected daily, kept in glass bottles until 

 evening, anesthetised with tobacco smoke and dissected. All possible 

 hiding places were included in the search. In March, the woods 

 afforded a more profitable collecting place, a horse being used to attract 

 the mosquitos. This was continued through March and April, and 

 discontinued when house infestation became general. In the region 

 investigated, true hibernation does not occur and the question of 

 hibernation was therefore not solved as a result of this study. Of the 

 Anophelines dissected between early February and the end of May, 

 there were 1,986 A. quadrimaculatus, 30 A. crucians, and 106 A. puncti- 

 pennis. No forms suggestive of malarial parasites were encountered. 

 As the result of various tests it was assumed that wintering mosquitos 

 were the predominant ones found until the latter part of April. To 

 determine the malarial indicator it is necessary to dissect a large 



