240 BACTERIOLOGY 



at ordinary temperature round colonies on the gelatine 

 plate, which liquefy in two days. Thrust-cultures show 

 a funnel-shaped excavation. On agar there forms a 

 greenish - white layer. Intraperitoneal injections into 

 white mice prove fatal with the symptoms of peritonitis, 

 and subcutaneous injections lead to the formation of 

 abscesses. 



Bacillus diphtheria. Klebs was the first to draw atten- 

 tion to the presence of bacilli in diphtheritic disease, and 

 Loffler has succeeded in producing similar morbid conditions 

 in animals by the injection of pure cultivations. The 

 bacillus is an imniotile straight or slightly curved rod of 

 the same length as the tubercle bacillus, but much thicker. 

 According to Loffler, it grows upon a nutrient medium 

 composed of 8 parts serum of sheep's blood, 1 part 

 neutralised veal bouillon, 1 per cent, of peptone, 1 per cent, 

 of grape sugar, and J per cent, of common salt ; and Kolisko 

 and Paltauf state that luxuriant growth takes place upon a 

 nutrient bouillon containing sugar, while Kitasato obtained 

 an abundant development upon glycerine agar. It should 

 be observed that the best temperature for all these experi- 

 ments is 33 to 37 C., and, speaking generally, the diph- 

 theria bacilli require for their development a heat of over 

 20 C. They retain their vitality even when completely dried, 

 and Loffler found them still capable of developing after 101 

 days. If diphtheritic membranes are protected from the 

 action of light and kept dry, cultures retaining their viru- 

 lence can be prepared from them after as long a time as 

 three months. They form upon gelatine small, round, 

 white colonies, with a coarsely granular texture and irregular 

 edges, and do not liquefy the medium. Little white dots 

 may be observed in the thrust-culture, and the rodlets often 

 assume altered shapes. The growth upon ordinary agar is 

 scanty, although luxuriant upon glycerine agar. A greyish- 



