METHODS OF STAINING TUBERCLE BACILLI. 39 



For certain organisms, micrococcus of pneumonia in sputum, micro- 

 coccus of gonorrhoea, &c, Klein recommends a mixture of methyl blue 

 and vesuvin. Gram's method appears, however, to be preferable for 

 the microccus of pneumonia, whether in sputum or in the tissues. 



Friedlaender succeeded in staining the pneumonia micrococcus in 

 the tissues by the following method. Stain the sections in 



Fuchsin, . * . . . i part. 



Distilled water, . . .100 parts. 



Alcohol, .... 5 parts. 



Glacial acetic acid, ... 2 parts. 



Afterwards rinse them first in alcohol and then in a two per cent, 

 solution of acetic acid, clear up in alcohol and oil of cloves, and 

 mount in balsam. 



Methods of Staining Tubercle Bacilli. 



27. The tubercle bacillus differs from most other bacteria in the fact 

 that it holds the aniline stains with great tenacity, even when acted 

 upon for a short time by a strong mineral acid, or for a longer time 

 by a dilute solution of one of these acids. 



The most favourable results are obtained if the thin layer of sputum 

 or thin section of tissue be first treated with some alkali such as 

 potash lye, or, better still, aniline oil. In place of an alkali, carbolic 

 acid one to twenty has been used, and with some success, and even 

 a one per cent, solution of bichloride of mercury. 



KocKs original method was as follows : — 



The cover-glass with the dried and coagulated film (§ 22, p. 26) is 



the clamp has the effect of driving out all the blood from the included tissues, 

 and the tubercle, from being dirty red, or purple, becomes like yellow wax. 

 The hold of the clamp is maintained at a degree of tightness sufficient to keep 

 up this state of anosmia, and at the same time the centre of the included mass 

 is pricked with a needle or sharp knife. From the puncture a droplet of perfectly 

 clear fluid exudes, and is to be transferred to one or more cover-glasses, each 

 cover-glass being smeared with rather a thick layer of the leper juice. The 

 cover-glasses are then dried, stained, washed, and mounted in the ordinary way. 

 The Weigert-Ehrlich method I have found gives good results. Under the 

 microscope, slides so prepared show bacilli in prodigious numbers, both free and 

 in dense bundles, packing the leper cells.' Klein recommends that the film be 

 stained with magenta, washed in distilled water, and then stained with methyl blue." 



