ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 711 



vessel, where they are dehydrated with spirit. The rest of the treatment 

 (clearing up and mounting in balsam) is done in the usual way. 



S H I M E B, H.— Section-cutting in the Cold. The Microscope, IX. (1889) pp. 275-7. 



C4) Staining: and Injecting-. 



New Method of Staining the Flagella and Cilia of Micro- 

 organisms.* — Prof. r. Loeffler has devised a new method for staining 

 micro-organisms, and which is especially intended to demonstrate cilia 

 and flagella. That the method is successful is shown by the results, 

 and in photograjjhs the flagella are perfectly seen, as also are cilia of 

 infusoria and monads. The method essentially depends on submitting 

 the preparations to the action of a mordant. 



From previous experience it had been found that the capsule of 

 pneumonia cocci were stained grey by ink. Hence tannate of iron sug- 

 gested itself, and after many trials the author hit upon the following 

 procedure which he pronounces to be satisfactory. 



The mordant is prepared by adding a watery solution of iron 

 sulphate to an aqueous 20 per cent, solution of tannin, until the whole 

 fluid turns a black violet. To this fluid is then added 3-4 cem, of log- 

 wood solution (1 part wood to 8 parts water). The solution should be 

 kept in well- stoppered bottles and 4-5 ccm. of a 5 per cent, solution of 

 carbolic acid added in order to keep it. 



The staining fluid is made by adding 1 ccm. of a 1 per cent, hydrate 

 of soda solution to 100 ccm. of anilin-oil water. This alkaline anilin 

 water is then mixed with 4-5 g. of methyl-violet, methylen-blue, or 

 fuchsin (solid) in a flask, and the ingredients mixed by shaking. When 

 required the requisite quantity of fluid is filtered off. 



The material to be examined must form a very thin layer upon the 

 cover-glass ; hence the fluid, &c., containing the bacteria must be diluted 

 with distilled water, and from the solution the specimen taken, so that 

 the film upon the cover is very thin. 



After having been dried in the air and fixed in the flame, the 

 mordant is poured over the film, and then the cover is held over the 

 flame until the fluid begins to evaporate. The mordant is then washed 

 off with distilled water, especial care being taken to remove all traces 

 from the edge of the cover. 



The next step is to filter a few drops of the stain (fuchsin best) upon 

 the film. This is allowed to act for a few minutes and then the cover 

 is very carefully warmed over the flame. As the fluid becomes warm 

 the film darkens, and when it is of a black-red hue the stain is washed 

 off with distilled water, and the preparation is then ready for micro- 

 scopical examination. 



Such is the principle of the author's method, but certain variations 

 are also given. One of these is for showing delicate spirals in prepara- 

 tions of typhoid and potato bacilli. Here a few drops of acetic acid 

 1^ per cent, are added to the solutions. It was also noticed that ferri- 

 tannate gave more satisfactory results with these bacilli than ferro- 

 tannate, but with other bacteria, such as those of cholera, the reverse 

 was the case. 



* Centralbl. f. Bakteriol. u. Parasitenk., vi. '1889) pp. 209-24 (8 pliotos.). 



