BACILLUS DIPHTHERIA 241 



white deposit is visible in forty-eight hours upon potatoes 

 which have been rendered feebly alkaline. 



For staining the bacilli in sections, the best solution to 

 employ is composed of 30 c.cm. alcoholic solution of methyl 

 blue in 100 c.cm. of 0-01 per cent, caustic potash (1 part 

 of caustic potash in 10,000 parts of water). A few 

 minutes are required for staining, after which the sec- 

 tions are placed for some seconds in per cent, acetic acid, 

 and then in absolute alcohol. Finally, they are treated with 

 cedar oil and mounted in balsam. The ordinary aniline 

 dye solutions have no effect. Besides the method of Loffler, 

 the 'negative result obtained with Gram's process is to be 

 considered a criterion of the presence of Loffler's diphtheria 

 bacilli. 



Various animals exhibit a high degree of sensibility 

 to infection with pure cultures of this micro-organism. 

 When the conjunctiva of young rabbits is slightly abraded 

 and smeared with a pure culture, they soon die, according 

 to Babes, and subcutaneous injections act with fatal effect 

 upon guinea-pigs in two days. Bacilli can be detected at the 

 point of inoculation, but all the remaining organs are free. 



Loffler obtained a whitish substance from the cultures 

 by extraction with glycerine and precipitation with alcohol. 

 It is soluble in water, and one or two decigrams when in- 

 jected hypodermically set up a haemorrhagic oedema and 

 cutaneous necrosis. Brieger and C. Friinkel state that 

 the poison extracted from the diphtheria bacillus belongs 

 not to the alkaloids but to the'toxalbumins. 



Numerous cocci are often found in the false membranes 

 of diphtheria, and these were formerly looked upon as the 

 cause of the disease ; some of them are, however, strepto- 

 cocci, the rest are saprophytes. According to Loffler and 

 Von Hoffmann, bacilli are frequently detected in the cavity 

 of the mouth and pharynx which morphologically and 



