54 CHEMICAL NATURE OF TOXINS 



vegetable toxins, such as ricin and abrin (which were thought to 

 be definitely proteid in nature), led, very early in the history of 

 the subject, to the view that these toxins are proteid in nature, 

 and this view was strengthened by the fact that when the diph- 

 theria or tetanus bacillus is grown in an albuminous fluid, proteid 

 substances which are toxic and give the specific reactions of the 

 toxins in question can be precipitated therefrom. Thus Hankin 

 and Sidney Martin found toxic albumoses in bacterial cultures, 

 and apparently succeeded in proving that abrin is an albumose. 

 Brieger isolated a toxalbumin from diphtheria cultures, and 

 Sidney Martin showed that from cultures of the same organism 

 in alkali albumin it is possible to prepare an albumose which 

 he thought to be the specific toxin. Many similar researches 

 were published, and the exotoxins were regarded as being albu- 

 minoid in nature, and the term toxoprotein was applied to them. 

 Several writers Duclaux in particular argued that this was 

 not the case, and thought that these proteid substances merely 

 carried the true toxins with them mechanically on precipitation, 

 just as the precipitates of inert substances such as cholesterin 

 will carry enzymes down with them. This theory was sup- 

 ported by Brieger and Cohn, who purified tetanus toxin from all 

 ordinary proteids, and especially by the researches of Buchner 

 and Uschinsky, who cultivated tetanus and diphtheria bacilli in 

 solutions devoid of all albuminous material, the necessary nitro- 

 genous nutriment being provided by asparagin. Under these 

 circumstances the toxic solution contains neither albumoses, 

 peptones, nor known proteids of any description. The toxins 

 thus formed are present in infinitesimally small amount, and have 

 never been obtained in a pure form, nor submitted to ultimate 

 analysis. It is known, however, that they contain nitrogen, that 

 they are readily destroyed by heat, and that they are dialysable. 

 These considerations lead us to the supposition that they are 

 closely allied to the proteids, and especially to the albumoses or 

 peptones, but form a group differing from any of them, and 

 approximating more closely to the enzymes. That this is the 

 case appears certain from the facts brought out by researches on 

 the antibodies ; all the substances of known chemical composition 

 which lead to the production of antibodies on injection into suit- 

 able animals are either proteids or else substances of indefinite 

 composition similar to the toxins, and apparently all proteids will 

 lead to the production of antibodies on injection into suitable 



