106 TOXINES AND ANTITOXINES. 



speedily renders the toxine non-poisonous, but leaves its im- 

 munising properties uninjured. Very similar results were 

 obtained by EHRLICH in experiments with carbon bisulphide. 

 It can hardly be doubted that there is here a rapid destruction 

 of the toxophore group with a survival of the haptophore group, 

 or in other words a, formation oftoxoid. Thymus extract appears 

 to have a similar result upon the growth, according to BRIEGER, 

 KITASATO, and WASSERMANN (loc. cit.). 



It appears to offer great resistance to putrefaction ; at all 

 events, SYMANSKI l found tetanus poison still present in decom- 

 posing cadaveric remains after forty-eight days. There is, 

 however, some reason for doubting whether this was true 

 tetanus poison. 



Concentration of the Toxine. Experiments with the object 

 of isolating the active principle from tetanus cultivations were 

 made at an early period. 



BRIEGER and FRANKEL prepared a "toxalbumin" by the method de- 

 scribed by them. VAILLARD obtained by evaporation of the solution of 

 poison in vacua a brown residue, which was insoluble in alcohol and could 

 be slowly dialysed. 



TIZZONI and CATTANI either simply dried the cultivations and 

 then dialysed them, or treated them with ammonium sulphate, 

 extracted the precipitate with water, and then used dialysis. 

 Subsequent evaporation in vacua then left solid toxines. 



BRIEGER and COHN 2 first treated the cultures with ammonium 

 sulphate. The precipitate was dissolved in water and part of 

 the proteids separated by means of very small quantities of basic 

 lead acetate and ammonia. The liquid was filtered from the 

 lead precipitate and salts, amino-acids and peptones removed 

 by dialysis. In this way they obtained a slightly Isevorotatory 

 solution of the toxine, which was free from sulphur and gave no 

 proteid reactions. They also prepared it from a proteid-free 

 culture medium similar to that of USCHINSKY (vide supra). 



Then BRIEGER 3 found that the poison could not be precipitated 

 by means of ammonium sulphate from very toxic solutions which 

 no longer contained albumoses. He endeavoured to effect a 

 further purification by precipitation with uranium acetate and 

 decomposition with metaphosphoric acid or lead acetate and 

 obtained preparations that no longer gave the biuret reaction. 



iSymanski, " Sitzungsbericht," Deutsch. med. Woch., 1901, 318. 



2 Brieger and Cohn, "Unters. lib. d. Tetanusgift," Zeit. /. Hyg. t xv., 

 1, 1893. 



3 Brieger, "Weit. Erfahrung. lib. Bakteriengifte," Zeit. f. Hyg., xix., 

 101, 1895. 



