BACTERIAL PROTEIDS. 21 



save peptone were employed. In this case they suppose 

 that the bacteria reconvert the peptone into an albumin. 



The poisonous proteids obtained by Beiegek and 

 Frankel from cultures of the Eberth germ, the comma 

 bacillus, and the staphylococcus aureus are practically in- 

 soluble in water, and more nearly related to the globulins 

 than the albumins, although they diif'er from the former 

 in their tardy and difficult solubility in dilute solutions of 

 sodium chloride. 



The poisonous proteids isolated by Vaugiian from cul- 

 tures of two species of toxicogenic germs found in drinking 

 water, suppOvSed to be the cause of typhoid fever, are solu- 

 ble in water, from which they are not precipitated by boil- 

 ing, or by concentrated nitric acid, or by both. Potassium 

 ferrocyanide and acetic acid, sodium" sulphate, magnesium 

 sulphate, and carbonic acid also fail to precipitate them. 

 They are precipitated by the general alkaloidal reagents, 

 and respond to the xanthoproteid, Millon, and biuret tests. 

 They are precipitated by ammonium sulphate when added 

 to saturation, and for this reason cannot be classed among 

 the peptones. Neither benzoyl chloride nor phenyl-hydra- 

 zin chloride precipitate them. Their poisonous properties 

 are destroyed by prolonged boiling or by being heated to 

 80° for some hours, though they remain active after an 

 exposure of ten minutes to the last mentioned temperature. 



Of the three bacterial proteids obtained by the same ex- 

 perimenter from the bacilli x, a and A of Booker's list of 

 summer diarrhoea germs, the first two are soluble in water, 

 while the other is not. So far as their behavior with pre- 

 cipitating agents is concerned, the first two agree with the 

 proteids of the water germs. 



TizzoNi and Cattani find that the proteid of cultures 

 of their tetanus germ is rendered inert by precipitation with 

 absolute alcohol. It is obtained by saturation with am- 

 monium sulphate, and the removal of the salt by dialysis. 



Further description of the individual proteids will be 

 given in subsequent chapters. 



2* 



