1058 SUMMARY OF CORRENT RESEARCHES RELATING TO 



specially favourable, on account of their large size and the rapid streaming, 

 as well as the readiness with which the colour is absorbed. 



Staining Pathogenic Bacteria with Anilin Dyes.* — Dr. C. Gunther, 

 when dealing with pathogenic bacteria, usually employs Ehrlich's anilin- 

 gentian solution, Loffler's potassium methylen-blue and Ziehl's carbolic- 

 acid fuchsin solution. Dry preparations stain better if before staining 

 they are washed with 1-5 per cent, acetic acid, and, if they have been kept 

 unstained for a long time, with a 2-3 per cent, watery pepsin solution. 



The author discusses Koch's method for staining tubercle bacilli with 

 the improvements of Ehrlich and Eindefleisch, and recommends the Ehrlich 

 procedure as the best and safest in practice. Gram's method is advised 

 for the pneumonia cocci of Friedlander and Fraakel, for the cocci of 

 pyaemia and erysipelas, for the bacilli of anthrax, lepra, and tubercle, and 

 for actinomyces. On the other hand. Gram's treatment is quite unsuited 

 for gonococci, bacillus of typhus, of glanders and of cholera, and also 

 for the spirochgete of recurrent fever. For preparations which have been 

 a long time in bad spirit and which resist decoloration by Gram's 

 method, the following modification is recommended : — Stain the sections 

 for 1 minute, dry with blotting-paper; decolorize for 2 minutes in the 

 iodide-iodine solution, then 1/2 minute in spirit, then 10 sec. in 3 per cent, 

 hydrochloric acid alcohol, after this the sections are transferred to spirit. 

 An inconvenience appertaining to Gram's method, in the deep-staining 

 of minute fat-globules, is best avoided by treating the specimen before it 

 is stained with chloroform, and then washing with absolute alcohol. In 

 order that the sections may be well stained it is advisable that not more 

 than two or three should be manipulated at a time, as decoloration is often 

 difficult. For double staining, the author recommends the ordinary nuclear 

 stains for contrasting with the stain of the micro-organisms. For erysipelas 

 sections stained by Gram's method, a double stain is best effected by 

 previously using ammonia-carmine or picrocarmine, a procedure which will 

 be found more suitable than after-staining. The preparations are best 

 mounted in xylol balsam ; and decoloration of tubercle and lepra bacilli, 

 both in sections and in cover- glasses, is most perfectly avoided by the dry 

 method as recommended by Unna. 



Staining the Bacillus of Glanders.f — ^Dr. G. M. Sternberg says that 

 these bacilli are best stained with a concentrated alkaline solution of 

 methylen-blue. For staining the bacilli in sections of tissue containing 

 them, Loffler recommends that they be immersed in the above-mentioned 

 solution for 12 to 24 hours, and then very carefully treated with very dilute 

 acetic acid until the sections have been decolorized sufficiently to bring the 

 bacilli into view. After this treatment they should be washed in alcohol, 

 and immersed in oil of cedar, which does not dissolve the anilin colours, 

 and is therefore to be preferred to oil of cloves in all preparations in which 

 these colours are used for staining bacteria. 



Anilin Stains.J — Dr. S. Griesbach's experiments on the anilin dyes lead 

 him to the conclusion that between the constituents of the dyes and those 

 of the tissues direct chemical combinations according to the laws of affinity 

 are effected, and therefore all those forces which have a promoting, retard- 

 ing, or destructive influence on affinity play a part in the staining process, 

 while above all influences is the capacity for a saturation of the tissues 

 with free gases, or, as Ehrlich expresses it, the gas saturation. The intro- 



* Deutsche Med. Wochenschr., 1887, No. 22. 



t Microscope, vii. (1887) p. 309, from Med. News, 



I Zeitschr. f. Wiss. Mikr., iii. (1886) pp. 358-85. 



