302 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(6) Miscellaneous. 



An Amateur's Introduction to Crystallography.* — Under this 

 title W. P. Beale has produced a very useful and serviceable treatise. 

 He states that it is his intention to help other amateurs to find 

 in the problems of Crystal Morphology occupation of practical in- 

 terest in itself leading to the more fascinating study of the optical and 

 other special properties of crystalline structures, and pointing to further 

 fields of study in molecular physics, which he (the writer) can only see 

 faintly and beyond his reach. At the same time the book does not 

 shirk difficulties. It commences with the study of an actual specimen, 

 and shows how the crystalline faces and edges can be connected with a 

 system of axes and co-ordinates, and so gradually leads up to an explana- 

 tion of the thirty-two systems. Methods of measurement and calculation, 

 are introduced, and special difficulties are reserved for two appendices. 

 The book is very clearly printed, and the illustrations are unusually 

 well done. 



B. Technique.! 

 (1) Collecting' Objects, including- Culture Processes. 



Detection of Trypanosomes in Animals. J — Muhlens draws attention 

 to the following method devised by A. Lundie § for the investigation of 

 trypanosomes. The suspected blood is allowed to run into a test-tube, 

 which contains a solution of 5 c.cm. of sodium citrate in 5 c.cm. of 

 sterile water, until the tube is three-quarters full. The contents are 

 then mixed by rolling in the hands. After about half an hour it will be 

 observed that a small quantity of clear fluid has separated out over the 

 blood layer. If trypanosomes are present they will be found in this 

 clear fluid layer. The author is of opinion that the development of 

 trypanosomes may be followed by this method, and that by the addition 

 of hydrochloric acid, the developmental cycle in the Glossina may be 

 simulated. 



Detection and Identification of Bacillus typhosus and B. para- 

 typhosus.|| — G. Dreyer, E. W. Ainley Walker, and A. CI. Gribson point 

 out that, in view of the importance at the present time of retaining con- 

 valescent soldiers under observation and control until they cease to act 

 as carriers, it is essential that the method used in making examinations 

 should be one in which a negative finding represents as nearly as possible 

 a true negative. The method of direct plating on so-called selective 

 media has often proved to be misleading. 



An extensive series of experiments was carried out with the media 



* Longmans, Green and Co., London, 1915, 220 pp., many figs. 



t This division contains (1) Collecting Objects, including Culture Pro- 

 cesses ; (2) Preparing Objects ; (3) Cutting, including Embedding and Microtomes ; 

 (4) Staining and Injecting ; (5) Mounting, including Slides, preservative fluids, etc. ; 

 (6) Miscellaneous. 



% Centralbl. Bakt., Ref. lxii (1913), p. 522. 



§ Journal of Tropical Medicine and Hygiene, xvii (1914), p. 22. 



|| Lancet, 1915, pp. 643-7. 



