SCIENCE-GOSSIP, 



MICROSCOPY 



CONDUCTED BY F. SHILLINGTON SCALES, F.R.M.S. 



Mosquitoes and Malaria. — The evidence in 

 support of the theory that malarial infection is due 

 to the bites of mosquitoes (see Science-Gossip, 

 Vol. vi., p. 182), themselves already infected, seems 

 now to have put the matter beyond a doubt. Drs. 

 Sambon and Low have deliberately taken up their 

 residence in the most unhealthy and fever-stricken 

 spot in the Roman Campagna, a place situated in 

 the heart of the swamp, among the haunts of 

 mosquitoes of the genus Anopheles, and of which 

 the few dwellings near at hand are inhabited by 

 peasants who are constant victims to malaria. 

 These daring investigators have shown that by 

 avoiding mosquitoes they avoid malaria, but a son 

 of Dr. Manson has given an even more striking 

 example of enthusiasm in the cause of science by 

 allowing himself to be bitten by mosquitoes which 

 had been fed on the blood of a sufferer from malaria 

 in Rome. The mosquitoes were sent to London by 

 Professor Bastianelli. and received early in July. 

 The patient, after being bitten, developed well- 

 marked malarial symptoms, though he has never 

 been in a malarial country since he was a child. 

 He has now recovered, but has thus supplied 

 evidence of the positive kind, as Drs. Sambon and 

 Low did of the negative kind. A letter from Mr. 

 H. J.Elwes, F.R.S., to the British Medical Journal, 

 calls attention now to the necessity of finding out 

 under what conditions mosquitoes do not produce 

 malaria, and mentions that whilst in certain dis- 

 tricts in India he escaped malaria by protecting 

 himself by mosquito curtains, whilst other members 

 of his party who omitted these precautions were 

 attacked, yet in other districts where mosquitoes 

 abound malaria is almost unknown, and these pre- 

 cautions were unnecessary. Amongst recent litera- 

 ture dealing with the subject we may mention a 

 paper on the life-histories of mosquitoes of the 

 United States, published in one of ihe Bulletins of 

 the U.S. Department of Agriculture, and con- 

 tributed by Dr, L. O. Howard, State entomologist. 

 Descriptions, with illustrations, are given of all the 

 members of the group met with in the United 

 States, with especial reference to members of the 

 genus Anopheles, to which suspicion most strongly 

 points. Dr. Howard advocates the use of kerosene 

 for the destruction of the larva, and calls attention 

 also to the agency of fish in this connection. The 

 July number of the Quarterly Journal of Micro- 

 scopical Science contains also a number of plates 

 and diagrams by Major Ross and Mr. R. Fielding 

 Ould, of the Liverpool School of Tropical Medicine, 

 illustrating the life-history of the parasites of 

 malaria. Before leaving the subject we may 

 mention that the second malarial expedition from 

 Liverpool has telegraphed home from Bonny, in 

 Nigeria, news of the discovery of another parasite, 

 found in the proboscis of mosquitoes, which causes 

 elephantiasis. Our readers will be aware of the 

 terrible scourge this disease is to millions of natives 



in tropical countries, and thai it is due to a small 

 worm which lives in the lymphatic- vessels. We 

 understand that the discovery has been simul- 

 taneously made in England by Dr. Low, and in 

 India by Captain James. 



Parasite prom Humble-bee.— I was much 



interested in the notes in the microscopical section 

 of the September SCIENCE-GOSSIP, especially those 

 mi the parasite of the humble-bee. Last year 1 

 mounted some parasites from a humble-bee which 



Pakasitk from Humble-bee. 



may possibly be identical with those referred to. 

 The size, however, is an objection, this one being 

 still larger than the specimen you comment upon. 

 The length, measured to the tip of the extended 

 jaws, is 1"5 mm. The length of the jaws, however. 



Jaws of Pakasitk. 



would vary, as they seem to be retractile. I enclose 

 a sketch which may be sufficient for identification. 

 — W. Cran, Mains of Lcs/noir, Rhynie. Aberdeen- 

 shire. 



Mr. C. Baker's New Catalogue. — Mr. Chas. 

 Baker has sent us his new catalogue, which is 

 increased in size by about twenty pages. It con- 

 tains particulars of his latest instruments, such as 

 the R.M.S. 1-27 microscope, the D.P.H. Nos. 1 and 

 2, the Diagnostic, and the Plantation microscopes, 

 all of which received notice in Science-Gossip 

 when they first came out for sale. The newest 

 pattern microtomes are also included. The list of 

 stains, mounting media, and other accessories, is 

 exceptionally complete and well arranged. Two 

 or three pages are devoted to pond-life apparatus. 

 but the extra pages are mainly taken np with lists 

 of microscopic slides, arranged mostly in series at 

 a moderate price, though the price of individual 

 specimens seems rather higher than usual. The 

 lists of bacteriological and diatomaceons slides call 

 for special notice. We have already drawn atten- 

 tion to Mr. Chas. Baker's excellent slide-lending 

 department. - 



