ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 237 



the obscuring effect of the massed corpuscles. The method depends on 

 the fact that the parasites adhere to the stromata of the containing 

 capsules, after the haemoglobin has been washed out of the films. A 

 thickish film of blood is spread on a slide over an area which can be 

 covered by the ordinary slip. It is then dried in the air or over the 

 flame. The dried film is then covered with aqueous solution of eosin 

 which is allowed to act for about a quarter of an hour. The film is then 

 gently washed to remove the superfluous eosin and at the same time the 

 hemoglobin. The film is then treated with a weak solution of methylen- 

 blue for a few seconds. After washing the film it is dried and mounted 

 in balsam. Prepared in this way the films show about twenty times 

 the number of parasites as are found in preparations of the same blood 

 made in the ordinary way. 



Method for Demonstrating: Nematocyst Cells in Hydra.* — E. 0. 

 Little puts living hydras in a Stender dish with a small amount of water. 

 A boiling-hot mixture of saturated solution of sublimate in 70 p.c. 

 alcohol is then poured into the dish. This kills the hydras in full 

 extension. After washing several times in 70 p.c. alcohol, the animals 

 are passed through 50 p.c. alcohol, 85 p.c. alcohol, and water successively, 

 after which they are stained for 5 minutes in the following solution : — 

 Methylen-blue 1 grm., Castile soap 0*5 grin., water 300 c.cm. The 

 animals are then passed hurriedly through the alcohols of the following 

 strengths : 30, 50, 70, 85, 90, 100 p.c, then cleared in cedar or bergamot 

 oil and mounted in balsam. The nematocyst cells are stained deep blue, 

 all other cells are unstained ; exploded nematocyst cells do not stain. 



New Method of Staining; Bacterial Granules.! — M. Ficker re- 

 commends a staining solution consisting of methylen-blue Hochst 

 1-10,000, lactic acid 2 p.c. The solution is made by dissolving 1 grm. 

 of methylen-blue in 100 c.cm. of distilled water and mixing 1 c.cm. 

 thereof with 100 c.cm. of distilled water. To 100 c.cm. of the last 

 solution 2 c.cm. of lactic acid are added. With this staining solution 

 a fresh unfixed bacterial suspension, placed on a slide and covered with 

 a slip, is treated by sucking the stain through with the aid of blotting- 

 paper and repeating the process several times if necessary. By this 

 procedure two or three dark blue granules appear, the rest of the bacterial 

 cell remaining unstained. 



Easy Method of Staining the Flagella of Bacteria. J — G. L. 

 Valenti says that just as good results can be obtained from gelatin, potato 

 and bouillon cultures, as from young agar cultures. The films are pre- 

 pared from emulsions in the usual way, and when carefully dried may 

 be kept for months before being used. The mordant used is a 20 p.c. 

 solution of tannic acid in distilled water, and the staining solution 

 Ziehl's fuchsin. The point of the method is to mix the mordant and 

 staining solution. The film is just covered with the mordant, then 

 three drops of the Ziehl's fuchsin solution are added. The cover-glass 

 or slide is then heated, and after having cooled is washed with water, 

 dried, and mounted in balsam. 



* Journ. App. Micr., vi. (1S03) p. 2116. 



t Hygion. Rundschau, 1902, p. 1131. See Centralbl. Bakt , 1" Abt. Ref., xxxii. 

 (1903) p. 723. t Centralbl. Bakt., 1" Abt. Ref., xxxii. (1903) pp. 1H 6. 



