678 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
fulfils every requirement for bacteriological work as it is easily taken 
to pieces, and its constituent parts easily disinfected by dry or moist 
heat, or by chemical agents. 
Staining the Flagella of Bacteria.* — Prof. F. Loeffler communicates 
a much improved method for staining the flagella of micro-organisms, 
the key to the procedure consisting in the greater or less acidity of the 
mordant. The quantitative differences in the reaction of the mordant are 
extremely slight, and vary with the different bacilli. 
The best results were obtained from using 10 ccm. of tannin solu- 
tion (20 + 80 water) to which had been added 5 ccm. of cold saturated 
ferrosulphate solution and 1 ccm. of aqueous of alcoholic solution of 
fuchsin, methyl-violet, or woolblack. This last pigment is used for 
dyeing wool without a mordant, and when dissolved in water is of a blue- 
black colour. 
The foregoing solution, especially when made up with fuchsin, is 
to be regarded as the stock solution, and one which will stain the flagella 
of certain micro-organisms such as Spirillum concentricum, but for others 
the addition of an alkali or an acid is necessary. Thus, for typhoid 
bacilli 1 ccm. of 1 per cent, caustic soda solution is required, while 
Bacillus subtilis needs 28-30 drops, the bacillus of malignant oedema 
36-37 drops, and so on. For cholera bacteria it is necessary to add 1 /2-1 
drop of sulphuric acid, for Spirillum rubrum 9 drops, to the 1 per cent, 
soda solution, the quantity of which is not however mentioned. 
This is the mordant and it differs from that previously given by the 
author by certain omissions, f 
The whole procedure now goes as follows. A small quantity of the 
pure cultivation is mixed up in distilled water, and with some of this 
the cover-glass is lightly smeared with a platinum loop. It is of the 
utmost importance that the cover-glass should be perfectly clean and free 
from grease or other impurities. The covers should be boiled in strong 
sulphuric acid, washed in distilled water, and having been immersed in 
ammoniated alcohol, dried on a clean cloth. 
The bacteria, when spread on, are fixed in a flame. For staining 
flagella this is absolutely necessary, but it is also as important not to 
over-heat. The correct amount of heat may always be estimated by 
holding the cover between the thumb and forefinger, instead of using 
forceps ; by this device overheating is avoided. While still warm, the 
mordant is applied. The cover-glass is then heated until it begins to 
vaporize (1/2-1 minute). It is then successively washed in distilled 
water and absolute alcohol. 
The staining solution is then dropped on in quantity sufficient to 
cover the cover-glass, which is again warmed until the solution vaporizes 
and then the cover-glass is washed in distilled water. 
The composition of the staining solution is ordinary neutral anilin 
water in which solid fuchsin is dissolved to saturation. To this as much 
of a 1 per cent., or still better 1 per thousand, soda solution is added 
as to bring it almost to the point of precipitation. Although it is not 
* Centralbl. f. Bakteriol. u. Parasitenk., vii. (1890) pp. 625-39 (8 photographs). 
t See this Journal, 1889, p. 711. 
