STAINING AND EXAMINATION OF MICRO-ORGANISMS 57 



Bacillus mesentericua vulgatus 4 drops of caustic soda to 16 c.c. of 



mordant 

 Micrococcus agilis . . .20 

 Typhoid baciUus . . .22 

 Bacillus subtilis . . 28 to 30 



„ cedematis maligni . 36 



„ of symptomatic anthrax 35 



Loffler's method not only stains the iiagella, but the 

 whole cell. In the ordmary processes of staining with 

 basic colours only the protoplasmic body of the micro- 

 organism is coloured, the outer covering but rarely 

 taking up any dye at all ; this process, however, colours 

 both the cell-wall and the protoplasmic contents, so 

 that when stained in this manner the bacteria look 

 thicker than when dyed in the ordinary way. 



A simple modification of the above method has 

 been more recently devised and successfully employed 

 by NicoUe and Morax.^ This consists in taking a small 

 quantity of a recent agar-culture of the organism and 

 diluting it in sterilised ordinarj^ water in a watch-glass ; 

 the liquid should be only very slightly turbid. A small 

 portion is then run on to cover-glasses, which must be 

 scrupulously clean and free from grease, for which 

 purpose it is advisable to first heat them thoroughly 

 by passing them several times through a bunsen-flame. 

 The cover-glass is held with forceps at one corner, and 

 after the liquid has spread over the surface the glass 

 should be slightly inclined, and the excess of liquid 

 which gathers at the opposite corner removed by 

 aspiration through a pipette, and the surface allowed 

 to dry, but protected from dust. A large drop of 

 the mordant or fuchsine-ink, prepared according to 

 Lofller's recipe,'^ is then run on to the cover-glass, 



^ * Technique de la Coloration des Gils,' Annales de VInstitut Pasteur, 

 vol. vii., 1893, p, 554. 



^ These authors mention particularly that the tannin must be of the 

 best quahty. 



