526 SUMMARY OF CURRENT RESEARCHES RELATING TO 



blood-films are fixed by heating them for 1-2 hours at 110°-120°. When 

 cool they are immersed in a saturated solution of thioniu for half an 

 hour. The preparations having been washed in running water are dried 

 and placed for 10-20 seconds in iodopotassic iodide solution (iodine 1 ; 

 iodide of potassium 2 ; distilled water 300). They are then washed 

 again, dried, and mounted in balsam ; the parasites are stained green. 

 Fresh solutions of thionin stain only faintly, but they act better if 

 heated till they vaporise, or by mixing 30 ccm. thionin solution with 

 15 ccm. of Loffler's methylen-blue solution. 



Stain for Nuclei of Endoglobular Hsematozoa.* — M. Laveran gives 

 some further directions for making a solution especially suitable for 

 staining the nuclei of endoglobular haematozoa. The stain is a mixture 

 of three solutions : — (1) In a 150 ccm. bottle are placed a few crystals 

 of silver nitrate and 50-60 ccm. of distilled water. When the crystals 

 are dissolved, the bottle is filled up with soda solution, and the precipi- 

 tated silver oxide is washed several times with distilled water. Saturated 

 aqueous solution of medicinal methylen-blue (Hochst.) is added, and the 

 mixture allowed to stand for seven or eight days ; (2) aqueous solution 

 of eosin 1 per 1000 ; (3) solution of tannin 1 per 100. 



When required for use, the stain is made by mixing 4 ccm. of the 

 eosin solution with 6 ccm. of distilled water and 1 ccm. of the methylen- 

 blue solution (Borrel's blue). The eosin and methylen-blue solutions 

 must be filtered separately at the time the mixture is made. The films 

 are treated in the usual way. 



Rapid Staining of Gonococcus in Fresh Unfixed Preparations.! — 

 Herr Uhma describes the following simple method for staining Neisser's 

 diplococcus. The advantages claimed are that the preparations require 

 no fixing, and that gonococci are distinguished from other bacteria by 

 the staining. The slides are moistened or smeared with an alcoholic 

 (or acetic acid) O'5-l per cent, solution of neutral red, and dried. A 

 small drop of pus is placed on a cover-glass, and the cover laid on the 

 slide. The preparation is then ready for examination. The gonococci 

 are the first elements to pick up the stain, and though very occasionally 

 other bacteria may be stained, this is the exception rather than the 

 rule. 



Staining Gonococci.:}: — Dr. E. Homberger states that he has used 

 Kresylecht violet, a fluorescing dichromatic pigment, for some years for 

 staining gonococci. The stain has a particular affinity for gonococci, 

 especially in quite dilute solutions, e.g. 1 to 10,000. With this solution 

 the nuclei of the cells become blue and the gonococci red-violet. Other 

 bacteria are but faintly stained or not at all. 



Even in sections Kresylecht violet possesses many advantages over 

 other pigments for staining gonococci. The sections are placed in 

 1 per cent, solution for several minutes, then transferred to alcohol, 

 followed by anilin oil-xylol in the proportion of two to one. If the 

 section is overstained it may be differentiated and dehydrated by means 



* C.E. Soc. Biol., lii. (1900) pp. 549-51. 



•j- Arch. f. Dermatol, u. Syph., 1. (1899) pp. 241-2. See Zeitschr. f. wiss. Mikr., 

 xvii. (1900) pp. 111-2. Cf. this Journal, ante, p. 264. - 

 % Centralbl. Bakt. u. Par., l' e Abt., xxvii. (1900) p. 533. 



