72 BACTERIOLOGY. 



mallein is another. According to Buchner and Romer, 

 all bacterial proteins are very similar in their action, 

 and Mathes maintains that deutero-alburuose, which is 

 obtained by the action of pepsin on albumin and has 

 no connection with bacteria, has an effect on tubercular 

 guinea-pigs somewhat similar to tuberculin. 



Toxins Active Proteids. Tox ALBUMINS. Fraenkel 

 and Brieger, confirming the statements of previous in- 

 vestigators (Christmas, Roux and Yersin, and Hankin), 

 have shown that amorphous poisons having an intense 

 and often specific toxic action that is an effect similar 

 to that produced by infection with the living organism 

 may be precipitated from bouillon cultures by agents 

 precipitating albumin. They therefore called these 

 poisons "toxalburnins," and regarded them as being 

 analogous to the toxalbumins of vegetable origin, like 

 ricin from the castor-oil bean (Ricinis communis), 

 and abrin from the jequirity bean (Abras precatorius). 

 The majority of investigators, however, consider these 

 poisons to be "labile" 1 albuminous substances, which 

 are derived from the bacterial cells. Some have assumed 

 that they were similar to snake poisons or to the 

 enzymes. Like these substances, they are very sensi- 

 tive to the action of heat, chemical agents, light, etc. 



Toxalbumins are obtained as crude substances by the 

 precipitation of the products of fully developed cultures 

 in bouillon under a vacuum, with absolute alcohol or 

 ammonium sulphate, after the culture fluid has been 

 freed from living germs by its passage through a por- 

 celain filter. When ammonium sulphate is used the 

 precipitate is freed from this reagent by dialysis 



1 So-called "labile" substances are such as are proue to undergo chemical 

 changes or alterations of atomic structure ; unstable. 



