TOX1NES PRODUCED BY BACTERIA. 137 



and even in tetanus the effects produced only bore a distant 

 resemblance to those caused by the injection of the 

 bacillus itself. Brieger's methods of obtaining these. bodies 

 were open to much criticism. The chemical processes 

 entailed were of a highly complicated character. They 

 commenced with a treatment of the crude material with 

 acids under heat, and this alone was shown to be sufficient 

 to cause serious changes in the complex albuminous bodies 

 present. The possibilities of similar changes occurring in 

 the subsequent stages of the analyses also existed, and this, 

 taken along with the failure of the bodies to reproduce the 

 toxic symptoms of their respective diseases, renders it un- 

 necessary for us to look on them as of other than a historic 

 interest. 



The introduction of the principle of rendering fluid 

 cultures bacteria-free by filtration through porcelain, and 

 its application by Roux and Yersin to obtain, in the case of 

 the B. diphtherias, a solution containing a toxine which 

 reproduced the symptoms of this disease (vide Chap. XV.), 

 encouraged the further inquiry as to the nature of this 

 toxine. The products of the B. diphtherias were investigated 

 again by Brieger, now in conjunction with C. Fraenkel. 

 The filtrate was evaporated to a third of its bulk in vacuo, 

 at a temperature not exceeding 30 C., and was precipitated 

 by alcohol. The precipitate was redissolved in water, repre- 

 cipitated by alcohol, and this operation being repeated six 

 to eight times a final product in the form of a snow-white 

 mass was obtained. The chemical procedure was thus 

 in principle simple, and the toxine at every stage stood the 

 two tests given by the original fluid, namely (i) its specific 

 toxicity to animals, and (2) destruction of its toxic power 

 by two hours' exposure to a temperature of 58 C. This 

 substance, if it did not consist entirely of the diphtheria 

 toxine, certainly contained the latter, and from resemblances 

 they observed in it to serum albumin, was called by its 

 discoverers a toxalbumin. Brieger and Fraenkel, working 

 with the same methods, obtained similar toxic bodies from 

 the bacteria of tetanus, typhoid, and cholera, and also from 



