136 ATLAS OF BACTERIOLOGY. 



They are also regarded as analogous to snake poisons 

 and to the enzymes. With these bodies they share a 

 great sensitiveness to heat, reagents, light, etc. 



The toxalbumins are obtained as a raw product by 

 precipitating, with absolute alcohol or ammonium 

 sulphate, old bouillon cultures of the bacteria which 

 have been concentrated in a vacuum, and which have 

 been freed from living germs by passing through a 

 porcelain filter. If the ammonia salt has been used, 

 this is removed from the filtered precipitate by dialy- 

 sis with flowing water in a parchment coil and, after 

 renewed concentration in a vacuum, precipitation of 

 the bodies with absolute alcohol. It has recently 

 been discovered that zinc chloride precipitates these 

 bodies quantitatively, and the toxins can be separated 

 from the precipitate by the aid of sodium phos- 

 phate (Brieger and Boer: Z. H., XXI., 268). 



From the beginning, however, doubts were ex- 

 pressed whether these toxalbumins were not merely 

 carried down by the precipitated albumin and perhaps 

 had no connection with the albumin. 



In the case of tetanus poison, Brieger and Cohn 

 (Z. H., XV., 1) succeeded in obtaining from the raw 

 product, by means of lead acetate and ammonia, a 

 pure virus which showed a faint violet color with 

 copper sulphate and soda lye but gave no albumin 

 reaction ; it is free from phosphorus and almost en- 

 tirely from sulphur. It thus seems to be proven that 

 the tetanus virus is not an albuminoid. 



The statements of Uschinsky that he obtained an 

 albuminoid tetanus virus and diphtheria virus upon 

 a non-albuminous nutrient medium have not been 

 tested hitherto because German observers did not 



