VITAL PHENOMENA OF BACTERIA. 73 



through parchment against running water, and after 

 concentration the substances are again precipitated by 

 absolute alcohol. Recently it has been found that zinc 

 chloride separates these bodies quantitatively, and that 

 the toxins may be obtained from this precipitate by 

 means of sodium phosphate (Brieger and Boer). 



All along, however, some doubt has been expressed 

 as to whether these so-called toxalbumins were really 

 only obtainable by precipitation from albumin or 

 whether they had anything to do with albumin at 

 all. With regard to tetanus poison, Brieger and 

 Cohn have now succeeded in obtaining what they 

 consider an almost pure toxin from the crude poison by 

 means of acetate of lead and ammonia. This substance 

 gives a slight violet color with copper sulphate and 

 soda solution, but otherwise no albumin reaction; it 

 contains neither phosphorus nor sulphur, and is appar- 

 ently not an albuminous substance. The statement 

 previously made by Uschinsky that he had obtained 

 albuminoid tetanus and diphtheria poisons in culture 

 media devoid of albumin could not, heretofore, be con- 

 firmed, owing to the difficulty experienced by most 

 investigators in getting a sufficient growth of these 

 organisms on such media. Brieger and Cohu have 

 found that cholera spirilla produce a non-albuminous 

 poison in Uschinsky' s culture media (free from albu- 

 min); and now diphtheria toxin has been recognized to 

 be non-albuminous (Brieger and Boer). It is becoming 

 more and more customary to call proteid bacterial poisons 

 simply toxins , irrespective of their composition, and to 

 ignore the existence of the above- described crystallizable 

 toxins of simple constitution., 



With regard to the other properties of these toxins, 



