ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 337 



razor. Then downward pressure on the stick cuts tho section, while 

 clockwise movement of the screw regulates the thickness. Serial sec- 

 tions are readily made if tho paraffin block is carefully squared ; but for 

 this work the^object-holder should be steadied by a weight W of five or 

 six pounds." 



(4) Staining: and Injecting:. 



Spore Staining.* — Dr. H. Marx stains spores in the following 

 simple manner : — A large loopful of culture or the condensation water is 

 placed on a cover-glass and carbol-fuchsin added. The mixture is boiled 

 four or five times successively, after which it is evaporated down to dry- 

 ness. The preparation is then decolorised in 25 p.c. nitric acid, and 

 after-stained with Loeffler's methylen-blue. 



By this procedure are stained not only spores actually formed but 

 such as are in process of formation. 



Simple Method for Staining Flagella.f — Dr. A. Peppier describes 

 a method for staining flagella, and gives numerous instances of its 

 success. The mordant is composed of tannin and chromic acid, and 

 is made by adding 15 parts of an aqueous sulphuric-acid-free 2*5 p.c. 

 solution of chromic acid to a solution of 20 parts tannin in 80 distilled 

 water. The latter is prepared by heating in a water-bath and cooling 

 down to 20°. The chromic acid is added in small portions and con- 

 tinually stirred the while. After standing for four to six days the 

 mordant is filtered. The staining solutions recommended are carbol- 

 gentian-violet, and carbol-fuchsin. For all bacteria except the spore- 

 formers it is advisable to use slides and not cover-glasses. Instructions 

 are given that the slides must be perfectly clean, after which follow 

 details for making the films from agar cultures. The films are air-dried 

 and fixed in the usual way. The mordanting and staining are carried 

 out at room temperature. The mordant is poured or filtered over the 

 slide and allowed to act for one to five minutes, according to the age of 

 the culture and other circumstances. The mordant is then poured off 

 and the slide washed in running water. The still wet slide is next 

 stained, the solution being allowed to act for two minutes. The slide is 

 thereupon washed and dried without delay on filter-paper. 



Anilin-blue for Staining- Bacteria. :f — MM. Guiraud and Gautie 

 lecommend a saturated aqueous solution of anilin-blue for staining 

 bacteria. The films are made in the usual way and then the stain poured 

 on. The cover-glass is heated two or three times successively until the 

 stain vaporises, after which it is washed in water and mounted. 



Staining Gonococci with. Neutral Red. — R. Herz§ uses a 0-5 p.c. 

 aqueous solution of neutral red placed on the slide, and on this is put a 

 cover-glass with a drop of pus. 



P. Bichter || uses ■ 25 p.c. aqueous solution of neutral red, made 

 with the aid of heat. The air-dried unfixed film is stained with a cold 

 solution. 



* Centralbl. Bakt., 1" Abt., xxix. (1901) pp. 11, 12 (3 figs.). 



t Tom. cit., pp. 315-55. 



J C.R. Soo. de Biol, de Paris, liii. (1901) pp. 190-2. 



§ Prag. Med. Wochenschr., 1900, No. 10. 



|| Dermatol. Zeitschr., vii. (1900) No. 2. See Centralbl. Bakt., xxviii. (1900) p. 71 1. 



