716 SUMMARY OF CURRENT RESEARCHES RELATING TO 



picro-carmin mixture by heating together 0*4 grm. earmiu, 100 ccm. 

 water, and 0'8 ccm. 10 p.c. caustic sod;;. While still hot, 25 ccm. of 

 0*5 p.c. aqueous solution of picric acid are added gradually. When 

 cold this sodium picro-carmin is mixed with half its bulk of 1 p.c. 

 HC1. The red precipitate which forms is then washed until the water 

 is no longer yellow. The dark red deposit on the filter is then dis- 

 solved in 70 p.c. alcohol acidulated with HC1 (about 1 p.c). The 

 solution is quite clear and gives good results after any method of fixation. 

 The immersion time is from a half to several hours. The after treat- 

 ment is simple and consists of changes of alcohol from 70 p.c. up to 

 absolute. The author states that the solution is an effective nuclear 

 stain, that by its use aqueous media can be avoided, and that it does 

 not colour celloidin. 



Flagella Staining.* — W. Kuntze describes the procedure he adopts 

 for staining flagella. The medium recommended for cultivating the 

 bacteria is the ordinary 1 p.c. meat-pepton-ugar but without salt. The 

 tubes need not be fresh. The cultures used for inoculating should 

 be from a few days to several weeks old and have been kept at the 

 room temperature for some time. The freshly sown tubes are in- 

 cubated and are ready for use in from 8 to 10 hours. An essential 

 for success is that the cover-slip should be perfectly clean, and 

 though a decent result may be attained by wiping, washing in ether 

 and flaming, it is safer to follow the procedures of van Ermengem and 

 Hinterberger. On the clean cover-slip is placed a drop of tap-water. 

 This is effected by means of a loop h— £ mm. in diameter and made by 

 bending a piece of glass rod. From this drop of water a droplet about 

 the size of a pin's head is removed and placed on another cover-glass- 

 To the latter is added a minute trace of the bacterial culture and the 

 suspension distributed into a thin layer by means of the glass loop-rod. 

 This must be performed without rubbing or pressing lest the flagella 

 be torn off or damaged. The film should dry in a few seconds ; it is 

 then fixed in the flame jin the usual way. When the film has cooled 

 it is mordanted with van Ermengem's fluid made about a week before. 

 The mordant consists of 1 vol. 2 p.c. osmic acid and 2 vols. 25 p.c. 

 tannic acid with four drops of acetic acid to 100 ccm. The mordanting 

 takes from \ to \ hour according to the temperature of the room. As 

 it is important that the preparations should not come in contact with 

 metallic substances, the cover-slips are held in glass-bladed forceps 

 during the rest of the manipulation. The films are next washed with 

 distilled water, and while still damp some 1 p.c. alcoholic solution of 

 silver nitrate is dropped on. After a few seconds they are treated with 

 the developer (5 grm. gallic acid, 3 grin, tannin, 10 grm. acetate of soda, 

 350 grm. distilled water). After a short action, silver nitrate solution 

 is again dropped on until the black precipitate, which forms at first, is 

 washed away. The films are then washed with distilled water, and if 

 it be found that they are clean and free from precipitate may be at once 

 passed through absolute alcohol and dried in the flame. If, however, any 

 precipitate still remain they must be treated with gold chloride solution 

 (1-2000 or 3000). Should it be necessary to use gold chloride the 



* Centrulbl. Bakt, 1" Abt. Orifj., xxxii. (1902) pp. 555-60 (1 fig.). 



