1044 SUMMARY OF CURRENT RESEARCHES RELATING TO 



closure of the air-pump is simultaneous with the opening of the gasometer. 

 It is of course obvious that experiments with this apparatus can only be 

 made up to one atmospheric pressure. 



Cultivation of Bacteria on Coloured Ifntrient Media, — Prof. A. v. 

 Eozsahegyi has experimented with the following Bacteria in order to 

 ascertain the effect of cultivation in coloured nutrient media, and the in- 

 fluence of the dye on their growth, and to acquire, if possible, a new 

 criterion for the differential diagnosis of the various species : — (1) bacilli 

 of blue milk and green pus ; (2) bacilli of rabbit septicaemia and fowl 

 cholera ; (3) bacilli of mouse septicaemia and swine plague ; (4) the Koch 

 and Finkler-Prior comma bacilli. 



The gelatin was stained with various anilin dyes, prepared in the 

 manner used for staining cover^glass preparations, and with " Tincture 

 Kermesina " (cochineal). A few drops of the stain were added to a small 

 flask of liquefied 5 per cent, gelatin, some of which was filtered into test- 

 tubes and sterilized by steam. When set, the gelatin was deeply stained, 

 but quite clear and transparent. The cultivations were made at a tempera" 

 ture of about 20° C, the ordinary temperature of a room. 



In the result, it was found that in certain cases it was evident to the 

 naked eye that the dye was taken up very freely (e. g, Finkler-Prior comma 

 bacillus in methyl-violet), and the bacilli seemed very deeply stained ; yet 

 on microscopical examination they appeared so pale that no advantage 

 accrued from the method of staining. The influence of the dye on the 

 growth of the bacteria was very various, although the alkaline reaction of 

 the gelatin was unchanged by the addition of the reagent. Yesuvin was the 

 most active preventive of growth, and less so gentian, methyl-violet, and 

 Tinctura Kermesina. The impa,irment of growth was most noticeable in 

 the liquefying varieties, and the form of the liquefaction area was also 

 altered; thus the Finkler-Prior comma bacillus, instead of growing 

 quickly down along the inoculation track, spread downwards in a broad 

 channel, presenting the appearance of a cultivation of Koch's comma 

 bacillus. In the latter the characteristic air^bubble was usually scarcely 

 visible, In the non-rliquefying varieties, the surface growth only was as a 

 rule impaired. 



In most cases the colouring matter was mnaffected by non-liquefying 

 bacteria, and where a change was observed, this began at the bottom of 

 the cultivation; the matter causing this decoloration must therefore be 

 produced in the absence of air. Of the liquefying comma bacilli, Finkler's 

 had no effect pn methyl-violet, while both this and Koch's comma bacillus 

 decolorized fuchsin in the fluid part, and methylen-blue in the solid. 

 "With methylen,-blue the colour could be restored on shaking, the effect 

 lasting in ^ cultivation of Koch's bacillus for days, but in one of Finkler's 

 a few hours only. 



With reg.ard to 4istinguishing between very similar kinds of bacteria, 

 the author found that rabbit geptic^mia did not grow in gentian, but very 

 strongly in vesuvin. Fowl cholera grew well in gentian, but not in 

 vesuvin. ]\Iouse septicEemia grew strongly in methylen-blue; swine 

 plague very poorly. Cultivation^ of the Finkler-Prior and Koch's comma 

 bacilli in fuchsin appeared pretty different ; in methylen-blue the former 

 lost colour more rapidly, and while it grew well, though slowly in methyl" 

 yiolet, Koch's bacillus would not grow at all. 



^ Centralbl, f, Bacteriol. u. ParasitecJf., ii. (1887) pp, 418-24, 



