338 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Method of Distinguishing Bacillus Coli Communis from Bacillus 

 Typhosus by the use of Neutral Red.* — W. Hunter has found that 

 Bacillus coli communis possesses, to a marked degree, the power of re- 

 ducing neutral red, producing a superb canary-yellow fluorescent colour 

 of the medium. The Bacillus enteritidis Gaertn. also produces this 

 reaction, and is probably only a variety of B. coli. Bacillus typhosus and 

 the common pathogenic microbes do not give the reaction. By means 

 of neutral red the presence of B. coli can be diagnosed with certainty 

 within from 12 to 24 hours, and it is possible, by means of this re- 

 agent, to distinguish members of the coli group from those of the typhoid 

 group. 



This method appears to be applicable only to tubes and not to plate 

 cultures. The most satisfactory medium is glucose-agar with 0*3 p.c. 

 of glucose. From 0*1 to 0*5 ccm. of a saturated aqueous solution of 

 neutral red are added to 10 ccm. of the medium. 



Diagnostic Staining of the Malaria 'Parasite.f — Dr. R. Beinhold 

 su<» fests that the films should be made by having the blood on the back 

 of the cover-slip which is drawn along the slide, so that the blood 

 follows instead of being pushed along. 



In fresh films he uses a solution made of 100 ccm. of water and 

 0-2 p.c. soda. This is heated, and to the boiling fluid 0*3 p.c. methylen- 

 blue (Hochst) is added. The solution is allowed to cool, and filtered 

 48 hours later. 



For films 4 weeks or more old, 1 p.c. methylen-blue must be added. 



Staining Diphtheria Bacteria.J — Dr. Piorkowski recommends the 

 following procedure : — Stain for 1 minute in Loeffler's methylen-blue 

 slightly warmed. Decolorise with 3 p.c. hydrochloric-acid-alcohol 5 

 seconds, wash with water, and after-stain with 1 p.c. aqueous eosin solu- 

 tion for 5 seconds. The superfluous water is removed by filter paper. 

 The preparations are to be examined in water, as the polar and central 

 granules are better seen. 



Modification of the Romanowski-Ruge Method of Staining Proto- 

 zoal — W. Hanna recommends Berestneff's modification of Romanowski's 

 method for staining the Plasmodium malarise and other Protozoa. A 

 1 p.c. aqueous solution of methylen-blue (Hochst) containing 0*3 p.c. 

 carbonate of soda, is heated for 3 hours in a water-bath and filtered. 

 One ccm. of this solution is mixed with 1 ■ 5 ccm. of a 1 p.c. aqueous 

 solution of methylen-blue, and to this mixture are added 5 ccm. of a 1 p.c. 

 aqueous solution of eosin (extra B A Hochst). Old preparations of 

 semilunar bodies and Halteridium DanielewsMi require 15 to 20 hours 

 at laboratory ('? incubator) temperature. Young forms stain in 15 to 20 

 minutes in alcohol, followed by gentle heating for 15 to 20 minutes. The 

 preparations are placed in the following solution for 2 to 5 seconds : — 

 10 ccm. methylen-blue 1 p.c, 200 ccm. distilled water, and 0*25 ccm. 

 acetic acid. They are next washed and dried, and then dipped for from 

 5 to 20 seconds in absolute alcohol, after which they are washed again 

 in water. 



* Lancet, 1901, i. pp. 613-5. 



+ Deutsch. Med. Wochenscbr., xxvi. (1900) pp. 447-S (1 fig.). 



X Zeitschr. f. angew. Mikr., vi. (1901) pp. 281-3. § Lancet, 1901, i. p. 1010. 



