150 STAINING TUBERCLE BACILLUS IN SECTIONS. 



Dr. Ratcliffe, being engaged in delicate experiments on the 

 spread of tuberculosis in the laboratory, was advised to try this 

 method, which seemed to present many advantages over the older 

 methods, when a few bacilli only are present in the organ. The 

 details published not being quite sufficient to obtain very satisfac- 

 tory results in every case, we worked out the details now given, with 

 the result that we can strongly recommend the following procedure : 



(i) Fix tissues by means of perchloride of mercury, acidulated 

 or not, and then harden in alcohol as usual. 



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



(3) Fix sections on slides by means of glycerine albumen in the 

 usual way. 



So far, there is nothing new in the method. 



(4) Stain with haematin solution for ten to twenty seconds to 

 obtain a pure nuclear stain (not too deep) ; then wash thoroughly 

 in water. 



(5) Stain now with Ziehl's carbonised fuchsin, kept at a tem- 

 perature of about 47° C. for twenty to thirty minutes. The slides 

 are during that time to be kept in a moist chamber to prevent the 

 stain drying on the specimen. 



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

 watery solution of hydrochlorate of aniline for a few seconds. 



(7) Decolourise in 75 per cent, alcohol till the section is appa- 

 rently free from stain ; this will take from fifteen to thirty minutes. 



(8) Double stain with a solution of orange (i per cent, of 

 saturated watery solution of orange to 20 to 40 parts of 50 per 

 cent, alcohol). 



(9) Dehydrate with absolute alcohol. 



(10) Clear very rapidly with xylol. 



(it) Mount in xylol and Canada balsam. 



Penicillium Cupricum. — Mr. J. de Seynes states that the 

 fungus called by this name is but a form of P. glaucum^ the 

 ordinary appearance of which it assumes when transferred to a 

 different medium. 



