BY DR. OSCAR KATZ. 571 



portion cannot be a spore, because it can be stained by the 

 ordinary aniline dyes within a short time, and without further 

 trouble. 



Noteworthy is that these bacilli retain the colour on being 

 treated after Gram's method (solution of aniline water and gentian- 

 violet ; solution of iodine in iodide of potassium; absol. alcohol). On 

 being stained with aniline water — gentian-violet, or — fuchsin, and 

 then transferred to a solution of hydrochloric acid (as used in 

 staining tubercle-bacilli), they give off the colour again. Double 

 or contrast stains may easily be obtained. Tolerably fair prepara- 

 tions were obtained by a dilute solution of gentian-violet, and by 

 after-staining with picro-lithion-carmine. Far better results, 

 however, were derived from transferring the sections first to a 

 solution of picro-lithion-carmine for -^-| of an hour, at about 

 30°C., next, after having been washed a short while in dilute 

 alcohol, to aniline-gentian-violet (s. above), for half-an-hour at the 

 same temperature ; hereafter rinsing a little with alcohol, then 

 allowing Gram's solution of iodine to act for about one minute and 

 a-half ] absol. alcohol; oil of cloves; Canada balsam.* The micro- 

 organisms then appear dark blue on a pinkish underground. Ecpally 

 satisfactory and very instructive preparations are obtainable by 

 first colouring the section with aniline-gentian-violet for about | 

 of an hour at about 30°C. ; washing a moment in alcohol, then 

 using the iodine-solution for one minute and a-half ; absol. alcohol 

 until colour is no longer given off; dilute watery solution of eosine 

 for 1-2 minutes ; mixtvire of absol. alcohol and oil of cloves ; oil 

 of cloves; Canada balsam. f After this process the organisms 

 come out deeply blue, while the tissue-elements (and another form 

 of bacteria, s. below), assume a handsome pink colour. 



*Cf. Biondi, Die pathogenen Micro-organismen des Speichels. Zeitschr. 

 f. Hygiene. Band II., Heft 2, Leipzig, 1887, p. 201. 



tCf. Biondi, I.e. 



