DIPHTHERIA TOXIN AND ANTITOXIN 479 



During the past year, the writer has had an opportunity to 

 study large scale manufacture of diphtheria toxin. This included 

 the preparation of thousands of liters of toxin having an L + dose 

 of 0.33 cc, 0.25 cc, or less, and its use in horses for immunization 

 purposes. It is the purpose of this article to consider the essen- 

 tials for the routine production of high potency diphtheria toxin 

 with special reference to its application in the development of 

 high strength antidiphtheric serum. 



II. THE PRODUCTION OF DIPHTHERIA TOXIN 



a. Culture to be employed 



Practically all of the institutions engaged in the propagation 

 of Corynebact. diphtheriae for toxin elaboration employ the strain 

 known as " Park- Williams bacillus no. 8" or "Culture Ameri- 

 cana." Recently, six cultures of this strain were obtained from 

 as many different laboratories. All were similarly carried by 

 transplanting from two twenty-four-hour generations on Loeffler 

 slant tubes and then in bouillon, according to technique later 

 described. A decided variation in the strength of the final toxin, 

 from the six cultures, was noted; two gave toxin of which one 

 L+ dose was greater than 0.5 cc. Only one, from the Hygienic 

 Laboratory of the United States Public Health Service, gave 

 toxin having an L+ dose of 0.25 cc. or less. The toxins from two 

 of the remaining three cultures gave L+ doses of 0.50 cc. and the 

 other one had a strength of L+ = 0.33 cc. The advisability of 

 verifying the toxicogenicity, particularly of any new strain of 

 the organism is apparent. The parent culture is best maintained 

 on slant tubes of moist Loefner blood serum, transplants to 

 bouillon being made as desired. 



b. Culture medium. 



Of the various media recommended for toxin elaboration with 

 Corynebact. diphtheriae, we have found plain beef infusion broth 

 containing 2 per cent peptone and 0.5 per cent sodium chloride to 

 be the most satisfactory. Extended trial with veal infusion in 



JOURNAL OF BACTERIOLOGY, VOL. V, NO. 5 



