222 



INFECTIVE DISEASES. 



The inoculated tubes are placed in the incubator. In a few hours 

 a whitish turbidity spreads out from the piece of tissue, and upwards 

 in the needle track. Examined microscopically, the turbidity is found 

 to be due solely to the development of the bacilli of oedema. The 

 surface exposed to the air exhibits no trace of the bacilli. To 

 investigate the tubes microscopically, a sterilised glass tube with a 

 capillary end may be used, with its neck 

 plugged with sterilised cotton-wool, and 

 provided at the mouth with a suction ball. 

 The capillary end is thrust into the cultiva- 

 tion, and a small fragment removed by 

 aspiration. 



In the course of the first day the bacilli 

 spread throughout a great part of the 

 agar-agar in such a way that a more or less 

 equally diffused cloudiness of the medium en- 

 sues, with subsequent appearance of strongly 

 marked clouds or lines of turbidity. At the 

 same time gas-bubbles develop along the 

 needle track, and a collection of liquid takes 

 place, while spore-formation also commences. 

 The following day these appearances are more 

 marked, the opacity is more pronounced, the 

 development of gas increases, and the liquid 

 contains more spore-forming bacilU and nu- 

 merous free-spores. 



The nutrient-gelatine cultures during the 

 first day show no macroscopic change, but 

 Fig. 104. Puke-cultuke ^fter * few days the piece of tissue is sur- 

 OF Bacillus oe Malig- rounded with a white halo. This gradually 



NANT (Edema in Gkape- spreads in all directions, and is apparently 

 buGAB Gelatine (Fran- ^ rr j 



KEL and Pfeiffek). l^eset with hairs. The gelatine liquefies, and 



the fragment of tissue, degenerated bacilli, 



and spores, sink to the bottom. The cultivation is also very 



characteristic in a | per cent, nutrient agar-agar. If placed in 



the incubator, in a few hours a cloudiness forms around the piece of 



embedded tissue, which is caused by bacilli gradually spreading in all 



directions in the nutrient medium. Mice inoculated from these 



cultivations die more quickly than from the original infection from 



dust. On potatoes they are cultivated by introducing a piece of liver 



or other tissue containing the bacilU, into the interior of a sterihsed 



potato, and incubated at 38° C. The bacillus is not deprived of its 



virulence by cultivation. 



