Metabolic Products 435 



The organism is highly susceptible to disinfectants except when 

 dried in false membrane. 



Metabolic Products. — The diphtheria bacillus forms acids (lactic 

 acid?) in the presence of dextrose, galactose, levulose, maltose, 

 dextrin and glycerin. It also forms acids in meat-infusion bouillon, 

 probably because of the muscle sugars it contains. In the absence 

 of sugars it produces alkalies. It is unable to evolv/e gas from any 

 carbohydrates. It does not coagulate milk; does not liquefy 

 gelatin or blood-serum. 



Palmirski and Orlowski* assert that the bacillus produces indol, 

 but only after the third week. Smith, f however, found that when 

 the diphtheria bacillus grew in dextrose-free bouillon no indol was 

 produced. 



Toxin. — The earliest researches upon the nature of the poisonous 

 products of the diphtheria bacillus seem to have been made in 1887 

 by L6ffler,t 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 belong 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 de- 

 generation 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, some- 

 times being preceded by marked emaciation. Temperatures 

 of s8°C. lessened the activity of the toxin and temperatures of ioo°C. 

 destroyed it. It was precipitated by absolute alcohol and mechan- 

 ically carried down by calcium chlorid. Brieger and Frankell|] 

 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 Ehrlichft 

 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 harmless 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 

 of the toxin molecules become changed into toxins or toxoids and 



*"CentralbI. f. Bakt. u. Parasitenk.," March, 1895. 



t "Jour. Exp. Med.," Sept., 1897, vol. n. No. s, p. 546- 



t"Centralbl. f. Bakt," etc., 1887, 11, p. 105. 



§ "Ann. de I'Inst. Pasteur," 1888-1889. 



II "Berliner klin. Wochenschrift," i8go, 11-12. 

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

 tt "Klinisches Jahrbuch," 1897. 



