182 



SCIENCE-GOSSJP. 



CONDUCTED BY F. SHII.LINGTON SCALES, F.R.M.S. 



The Malaria Parasite. — Our readers can 

 hardly fail to have been interested in the recent 

 investigations of Major Ross, R.A. M.C., into causes 

 and disseinination of malaria ; investigations which 

 appear to have solved the hitherto apparently 

 insoluble problem as to the mode of life of the 

 parasites to which malaria has now been traced, and 

 to have given the final coup de grace to the old theory 

 ihat it is connected with a certain condition of the 

 soil. It is now placed beyond a doubt that malaria is 

 due, and probably due only, to a parasite belonging 

 to the family Haemaoebidae, passing a stage of its 

 existence in the stomach of certain mosquitoes, and 

 by the bites of the latter infecting the blood of man. 

 The life-histoiy of these parasites has been com- 

 pletely followed by Major Ross in Ciilex pipiens and 

 confirmed by others in Anopheles claviger. We 

 would refer those who desire fuller information on 

 this point to a paper by this investigator in 

 "Nature" for August 3id. The interest now lies 

 in the question of the exact species of mosquito rather 

 than that of the parasite. Major Ross, in more than 

 one report has adduced facts in support of his strong 

 belief that the dissemination of malaria is confined 

 only to the comparatively rare "spotted-winged" 

 mosquito, belonging to the genus Anopheles., and 

 which has been traced to two species in India and to 

 one in Italy. Other and commoner forms of mosquito, 

 such as the "brindled" and "grey" mosquitoes, 

 are believed to be quite harmless, if painful, in their 

 bites, though Koch has traced malaria in Tuscany to 

 the bites of C;//c.i-/;)>/t'«i-. If this should be finally 

 placed absolutely beyond a doubt, it will be of the 

 greatest importance not only to our military stations 

 and camps, but to many crowded districts, towns and 

 cities. Mosquitoes of the genus Ctilex breed 

 in artificial collections of water, such as 

 pots and tubs, cisterns, wells, and drains, 

 but those of the genus Anopheles breed or are 

 developed from larvae or grubs found only in natural 

 ponds and puddles of stagnant water in which green 

 algae are growing, and seldom in larger bodies of 

 water such as tanks or streams, where they would be 

 liable to be devoured by minnows, etc. Still, whether 

 confined to the genus Anopheles or not, it seems cer- 

 tain that the flies breed in puddles, and are not of the 

 common or domestic kind. If this be so, and it can 

 be placed beyond question that these mosquitoes breed 

 only in spots sufficiently isolated to be dealt with by 

 public measures of repression, and that the malaria 

 from which perhaps a large town is suffering can be 

 abated by the filling up or otherwise treating with 

 simple means a few small puddles, we have arrived at 

 a result of investigation that cannot easily be over- 

 estimated. It has already been found for instance, 

 that a drachm of paraffin oil poured on the surface of 

 a pool about a square yard in area has been sufficient 

 to kill all the Anopheles larvae in six hours. It was 

 to solve these matters finally that the Liverpool School 

 of Tropical Medicine sent out its recent well-equipped 

 expedition to Sierra Leone, to follow up the work 



done by Major Ross in India, and to put the method.-- 

 suggested to practical proof. Every assistance was 

 given them by the Government, and as we understand 

 that the expedition returned on October 7th to this 

 country, well satisfied with their labours, we may look 

 for an interesting report. It may be noted, in con- 

 clusion, that only one member of the expedition, Mr. 

 E. Austin, Assistant in Diptera, British Museum, 

 became infected with malaria, through sleeping one 

 night without mosquito-curtains. 



Baker's Diagnostic Microscope.— In connec- 

 tion with the foregoing note on the malaria parasite, 

 it will probably interest our readers if we illustrate 

 and describe the microscope originallv designed for 

 Major Ross, R.A.M.C, by Mr. Chas. Baker, of 

 High Ilolborn, and used by him throughout his 

 research. As will be seen, it stands upon a light but 

 rigid tripod, with a spread of 7in., has coarse and 

 fine adjustment, condenser with iris diaphragm, plane 

 and concave mirrors, etc. The whole packs into the 

 neatest of leather cases, i lin. Xsiin. X3in., furnished 

 with a strap for the shoulder, and loops for a military 

 belt. The case is lined with baize or soft chamois 

 leather. There is yet room for two eye-pieces and 

 three objectives, two bottles of stains, and a bottle of 

 immersion oil, together with a double nose-piece, but 

 the total weight is only four pounds. Altogether, the 

 w hole is a marvel of compactness, and well thought-out 

 efficiency. The microscope will focus satisfactorily a 



Baker's Diagnostic Microscope. 



-j'Trin. immersion lens, and is, we think, the best 

 travelling miscroscope sold. We have for some years 

 had one in our own use when travelling, and can 

 speak highly of it. It may interest our readers to 

 know that as we write Messrs. Baker are despatching 

 outfits for the use of the Medical Staff at the Cape, in 

 connection with the Transvaal war. We may add 

 that, as described above, with all extras, including 

 Jin., ^in., and I'^in. imm. objectives, the outfit 

 costs ;^I3 7s. 6d., but the microscope itself, in case, 

 can be bought for ;^3 12s. 6d., or w=ith sliding coarse 

 adjustment only, £2 7s. 6d. 



