THE MICROSCOPE. 177 



edge. The following is the process described by the author for de- 

 tecting the bacilli: 



"There is, so far as I know, no other method but Ehrlich's now 

 in use for staining the bacillus of tubercle. Various modifications of 

 his process have been suggested; but in all points of importance it 

 remains as it was given to us by Ehrlich himself. The modifications, 

 which are improvements of this process, aim at giving the staining 

 mixture a uniform composition; and several different formulae have 

 been suggested for that purpose. The one now in use in this hos- 

 pital, and I have myself used it for some months past, is Weigert's. 

 Its composition is saturated alcoholic solution of fuchsin, or meth- 

 yline violet or gentian violet, 11 parts; anilin water 100 parts. 



"In warm weather good results are to be obtained when the 

 staining process is carried out at summer temperature, and without 

 the use of artificial heat. I should advise you, however, always to 

 stain your specimens while they are exposed, in an incubator of some 

 kind, to a temperature of 98 to ioo° Fahr. Want of attention on 

 my part to this important point caused me much inconvenience when 

 the cold weather set in last autumn. 



"The process I have just described to you occupies some time. 

 It has, however, certain advantages. Not only does it ensure thor- 

 oughly good staining of the bacilli, but the specimens, while being 

 stained, may be safely left for from half an hour to ten hours, or 

 even longer, in the fuchsin and anilin mixture, just as the experi- 

 menter finds most convenient. There is, however, a more rapid way 

 of staining. The same staining fluids are used. A little of the 

 fuchsin dye is filtered into a watch-glass, the specimen to be stained 

 is placed in the fluid, and heat is applied. I have been accustomed 

 to apply the heat by lighting a Bunsen burner, not at the top of the 

 funnel, but at the burner itself. The heat, of course, passes up the 

 Bunsen funnel, and so reaches the watch-glass, placed at a conveni- 

 ent height upon a tripod. I find that one minute's exposure to the 

 action of the staining fluid, under these conditions, is sufficient to 

 ensure excellent coloring of bacilli in sputum or in pus. The rest 

 of the process is identical with that I have already described to you. 

 Following this plan, it is easy to stain, and examine with the micro- 

 scope, a specimen of sputum within ten minutes' time. Most of the 

 specimens of the tubercle-bacillus in sputum and in pus which you 

 see here to-day, have been prepared in this rapid way. In speaking 



