74 TOXINES AND ANTITOXINfiS. 



SpRONCK 1 subsequently abandoned his meat extract and 

 cultivated his bacilli in a decoction of yeast, whereby he obtained 

 very active solutions of poison. (After forty-eight hours the 

 lethal dose was 0*05 c.c., and after five to six days 0*005 c.c.) 



He boiled 1 part of commercial yeast with 20 parts of water for twenty 

 minutes with continual stirring. He then allowed the mixture to settle, 

 decanted the supernatant liquid, added ordinary salt and Witte's peptone 

 (obtained directly from Rostock), neutralised it, and added normal soda 

 solution in the proportion of 7 c.c. per litre. Lastly, he heated and filtered 

 the liquid, and sterilised the filtrate at 120 C. 



It is evident from these experiments that the production of 

 toxines depends upon the alkalinity of the medium, and, as 

 Roux and YERSIN had already found, it increases with the in- 

 crease in the alkalinity. MADSEN, however, found (loc. cit.) that 

 the amount of toxine was not invariably proportional to the 

 alkalinity. 



A second method of increasing the yield of toxine is the intro- 

 duction of air. Roux and YERSIN found that a current of air 

 promoted the production of poison, although, according to 

 MARTIN (loc. cit.) and PARK, 2 this stimulation is not very pro- 

 nounced, provided culture media, good in other respects, are 

 employed ; whilst MADSEN considers it directly injurious in such 

 a case, on the ground that when there is a plentiful production 

 of toxine the air destroys a greater amount of poison than is 

 formed under its influence. SPRONCK, too, is inclined to believe 

 that while the growth of the bacilli, and therefore the absolute 

 production of toxine, is promoted by the admission of air, yet 

 that the relative production of toxine by a given number of 

 bacilli is thereby diminished rather than increased. VAN 

 TURENHOUT (loc. cit.) considers that the admission of air 

 accelerates the oxidation of the nitrogenous substances, arid with 

 it the cessation of the acid reaction, but that it also destroys 

 poison. ARONSON 3 has very successfully replaced the introduc- 

 tion of air by growing the bacteria in surface cultivations, so that 

 they offered as large an area as possible to the air. SCHIERBECK 4 

 recommends treatment with carbon dioxide. 



1 Spronck, "Preparation de la toxine diphterique," Ann. Past., xii., 

 701, 1898. 



2 Park, " The Preparation of Diphtheria Antitoxine," Med. Record, 

 xlvii., 484, 1895. 



3 Aronson, " Immunisierungs- und Heilversuche bei der Diphtheric," 

 Wien. med. Woch., 1894, 1956. 



4 Schierbeck, " Ueb. d. Einfluss der C0 2 auf das Wachstum der Diphth.- 

 B.," Arch. f. Hyg., xxvii., 339, 1896. 



