230 BACTERIOLOGY 



nitric acid and ten of alcohol, rinsed in water, and double- 

 stained in an aqueous solution of methyl blue. 



According to Lustgarten, cover-glass preparations, after 

 staining in aniline water solution of fuchsine or gentian 

 violet, are decolorised in one per cent, sodium hypochlorite 

 and rinsed in water. 



Unna stains sections for twelve to twenty-four hours in 

 aniline-water fuchsine, and decolorises in a ten to twenty per 

 cent, aqueous solution of nitric acid until the preparations 

 have acquired a yellow colour, after which they are 

 transferred to dilute alcohol, and left there until the tint 

 has turned red. The acid still present is now removed by 

 immersion in a weak solution of am- 

 monia in water, and the water is ab- 

 sorbed up with blotting-paper, after 

 which the preparations are mounted 

 in balsam free from oil, dissolved in 

 chloroform. 

 FIG. 86. ISLET OP LEPRA The Lutz-Unna method consists in 



BACILLUS ON A GELA- 



PLATE> (After staining the preparations in a warm 



aniline-water solution of gentian violet 

 until they have become darkly-coloured, after which they 

 are decolorised by successive immersion in solution of 

 iodine and potassium iodide, in alcohol and nitric acid, and 

 in plain alcohol. This procedure must be repeated until 

 the preparations show a bluish slate-colour, after which 

 they are mounted in balsam dissolved in oil of thyme or oil 

 of cloves. 



Cultivation of the bacilli succeeded in the hands of 

 Bordoni-Uffreduzzi upon peptone glycerine serum, which 

 was inoculated with marrow from the bones of a person 

 who had died of leprosy. From this it was possible to 

 transfer the microbes to gelatine, on which they form 

 rounded colonies at 20 to 25 C. without liquefying the 



