Metabolic Products 479 



Spronk * found that the characteristics of the growth of 

 the diphtheria bacillus in bouillon, as well as the amount 

 of toxin produced, vary according to the amount of glucose 

 in the bouillon. 



Zinnof found that digested brain added to the culture 

 bouillon greatly facilitated the growth of diphtheria and 

 tetanus bacilli and increased the toxin-production. 



Blood-serum. The bacillus grows similarly upon blood- 

 serum and Loffler's mixture. 



Potato. Upon potato it develops only when the reaction 

 is alkaline. The potato growth is not characteristic. 



Milk. Milk is an excellent medium for the cultivation of 

 Bacillus diphtheriae, and is possibly at times a medium of 

 infection. Litmus milk is useful for detecting the changes 

 of reaction brought about by the alkalinity, which at first 

 favors the development of the bacillus, being soon replaced 

 by acidity. When the culture becomes old, the reaction 

 again becomes strongly alkaline. This variation in reaction 

 seems to depend entirely on the transformation of the sugars. 



Vital Resistance. The diphtheria bacillus does not 

 form spores. It possesses very little vital resistance and 

 is delicate in its thermic sensitivity. Loffler found that it 

 could not endure a temperature of 60 C., and Abbott has 

 shown that a temperature of 58 C. is fatal to it in ten 

 minutes. The organism can sometimes be kept alive for 

 several weeks after being dried upon shreds of silk or when 

 surrounded by dried diphtheria membrane. 



Metabolic Products. The earliest researches upon the 

 nature of the poisonous products of the diphtheria bacillus 

 seem to have been made in 1887 by Loffler, { who came to 

 the conclusion that they belonged to the enzymes. The 

 credit of removing the bacteria from the culture by filtration 

 through porcelain and the demonstration of the soluble 

 poison in the filtrate belongs to Roux and Yersin. Toxic 

 bouillon prepared in this manner was found to cause serous 

 effusions into the pleural cavities, acute inflammation of 

 the kidneys, fatty degeneration of the liver, and edema 

 of the tissue into which the injection was made. In some 

 cases palsy subsequently made its appearance, usually in the 



* "Ann. de 1'Inst. Pasteur," Oct. 25, 1895, vol. ix, No. 10, p. 758. 

 f "Centralbl. f. Bakt.," Jan. 4, 1902, xxxi, No. 2, p. 42. 

 J "Centralbl. f. Bakt.," etc., 1887, n, p. 105. 

 "Ann. de 1'Inst. Pasteur," 1888-1889. 



