ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 401 



(2) Preparing' Objects. 



Method for Demonstrating Spores of Tubercle Bacilli.* — L. von 

 Betegh employs the following method for demonstrating the spores of 

 tubercle bacilli. Thin smears are prepared, dried, and fixed in the 

 flame ; these are then placed in 10 p.c. nitrate of silver, and heated for 

 one minute at 80°-90°C. (but not allowed to boil), and then thoroughly 

 washed in water ; they are then treated with several drops of freshly 

 made 50 p.c. aqueous solution of rodinal, for 20 to 30 seconds, until 

 they become brown or black-brown ; again washed in water, dried, and 

 mounted. By this means only the spores are stained black-brown, and 

 the organism may be subsequently stained by treating the film with 

 carbol-fuchsin, without warming, for 1-2 seconds. 



Hahn, H. — Apparat zur Einbeltung in paraffin. 



[A. sideboard into which is let a tank, with hot and cold water supply, 

 worked through a 3-way tap by means of a pedal. In order to regulate 

 the temperature of the water in the tank, this is divided up by a number 

 of partitions.] Zeitschr. Wiss. Mikrosk. xxv. (1908) pp. 184-7 (2 figs.). 



C4) Staining: and Injecting-. 



Methods for Staining Tubercle Bacilli.f — A. Cann compares the 

 methods of Ziehl-Neelsen, Much, and Hermann. The methods of 

 Much consist of several modifications of Grain's method ; Hermann's 

 stain is a solution of crystal-violet and ammonium carbonate, and 

 various modifications for this stain when used for sections are suggested. 

 The author finds from the examination of a number of specimens 

 stained by these processes that both the method of Much and those of 

 Hermann compare favourably with that of Ziehl-Neelsen ; that many 

 cases which are negative with Ziehl-Neelsen are also negative with the 

 other methods ; but twice as many cases which gave a positive result 

 with Hermann's methods were negative with Ziehl-Neelsen, and a less 

 number were negative with Mnch's method. Granules and granular 

 rods are more often demonstrated by the methods of Much and Hermann 

 than by Ziehl-Neelsen. 



Ma sue, A.— Beitrage zur Histologie u. Entwicklungs-gescb.icb.te der Schmelz- 

 pulpa. Anat., xxxv. (1907) pp. 265-92 (6 pis.). 



(5) Mounting-, including- Slides, Preservative Fluids, etc. 



Mounting of Algge.J— J. A. Nieuwland calls attention to G. S. 

 West's method of killing, fixing, mounting, and preserving alg£e. 

 The fluid used is a 2 p.c. solution of potassium acetate, made just 

 blue with copper acetate. This medium reduces plasmolysis to a 

 minimum. For permanent mounts thick slides should be used, and the 

 coverslip sealed down with gold size several times after each drying. 



With Vaucheria, plasmolysis is hard to avoid, and the best pro- 

 cedure is to kill rapidly with 3 or 4 p.c. formalin, which must be com- 

 pletely washed out afterwards, or the preparations will turn black. 

 The Vaucheria are then removed to 5 to 10 p.c. glycerin, to which a 



* Centralbl.Bakt., lte Abt. Orig., xlix. (1909) p. 461. 



t Tom. cit., p. 637. \ Bot. GBm;., xlvii. (1909) pp. 237-8. 



June 16th, 1909 2 e 



