264 THE AMERICAN MONTHLY [Aug 



after using- a method in some researches in tuberculous 

 lesion, has strongly recommended the following- : 



After the sections have been stained in the usual way by 

 means of carbolised fuchsin, they are placed for a short 

 time in a solution of hydrochlorate of aniline, and after this 

 they are left in alcohol till quite decolorized, when it is 

 found that though the fuchsin has been removed from 

 all the tissues, the tubercle bacilli remain deeply stained. 



This method, therefore, resembles very closely the 

 Gram's method, with the difference that, instead of 

 Gram's iodine solution being- used to fix the stain in the 

 bacilli, in this case it is Kuhne's hydrochlorate of aniline 

 which is used. 



Dr. Ratcliff, being- engag-ed in delicate experiments on 

 the spread of tuberculosis in the laboratory, was advised 

 to try this method, which seemed to present many advant- 

 ag-es over the older methods, when a few bacilli only are 

 present in the org-an. The details published not being- 

 quite sufficient to obtain very satisfactory results in every 

 case, we worked out the details now g-iven with the result 

 that we can strong-ly recommend the following- procedure: 



(1) Fix tissues by means of perchloride of mercury, 

 acidulated or not, and then hardened in alcohol as usual. 



(2) Embed tissues in parafdn, using- toluol as a solvent. 



(3) Fix section on slides by means of g-lycerine albu- 

 men in the usual way. 



So far, there is nothings new in the method. 



(4) Stain with haimatin solution for ten to twenty 

 seconds to obtain a pure nuclear stain (not too deep) ; then 

 wash thoroug-hly in water. 



(5) Stain now with Ziehl's carbonized fuchsin, kept at 

 a temperature of about 47 deg-rees C. for twenty to thirty 

 minutes. The slides are during- that time kept in a 

 moist chamber to prevent the stain drying- on the speci- 

 men. 



(6) Remove the stain and treat the section with 2 per 

 cent watery solution of hydrochlorate or aniline for a few 

 seconds. 



(7) Decolorize in 75 per cent alcohol till the section is 



