Metabolic Products 427 



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.f 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 

 hind quarters. The effect of the poison was slow and death 

 took place days or weeks after injection, sometimes being 

 preceded by marked emaciation. Temperatures of 58 C. 

 lessened the activity of the toxin and temperatures of 100 

 C. destroyed it. It was precipitated by absolute alcohol 

 and mechanically carried down by calcium chlorid. Brieger 

 and Frankel J confirmed the work of Roux and Yersin, and 

 concluded that the poison was a toxalbumin. Tangl 

 was able to extract the toxin from a fragment of diphtheria 

 pseudo-membrane macerated in water. 



The nature of the diphtheria toxin has been studied by 

 Ehrlich || and found to be extremely complex. As it 

 exists in cultures it is composed of equal parts of toxin and 

 toxoid. Of these, the former is poisonous, the latter harm- 

 less for animals or at least not fatal to them. The toxoids 

 have equal or greater affinity for combining with antitoxin 

 than the toxin and cause confusion in testing the unit value 

 or strength of the antitoxin. In old or heated toxin all 



* "Centralbl. f. Bakt.," etc., 1887, u, p. 105. 

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

 t" Berliner klin. Wochenschrift," 1890, 11-12. 

 "Centralbl. f. Bakt.," etc., Bd. xi, p. 379. 

 || " Klinisches Jahrbuch," 1897. 



