Metabolic Products 417 



when dried on paper, silk, etc., continues for but a few days, though 

 sometimes they can live for several weeks. In sand exposed to a 

 dry atmosphere the bacilli die in five days in the light; in sixteen 

 to eighteen days in the dark. When the sand is exposed to a moist 

 atmosphere, the duration of their vitality is doubled. In fine; 

 earth they remained alive seventy-five to one hundred and five 

 days in dry air, and one hundred and twenty days in moist air. 



The organism is highly susceptible to disinfectantsexc ept when 

 dried in false membrane. 



Metabolic Products. — The diphtheria bacillus forms acids (lactic 

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

 dextrine 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 evolve 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 iri 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, 

 sometimes 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 

 mechanically carried down by calcium chlorid. Brieger and 

 Frankelll confirmed the work of Roux and Yersin, and concluded 

 that the poison was a toxalbumin. Tangl** was able to extract the 

 toxm from a fragment of diphtheria pseudo-membrane macerated 

 in water. 



The nature of the diphtheria toxin has been studied by Ehrlichft 



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



t "Jour- Exp. Med.," Sept., 1897, vol. 11, No. s, P- 546- 



fCentralbl. f. Bakt," etc., 1887, 11, p. 105. 



§"Ann. del'Inst. Pasteur," 1888-1889. 



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

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

 tt"Klimsches Jahrbuch," 1897. 

 27 



