LESSON II 



Proteines Precipitation of Proteines by Alcohol Bacterial Extracts. 



Prote'ines (Nencki, Buchner, Rdmer) 



(a) Bacillus pyocyaneus. 



(1) Inoculate twenty agar-agar tubes with the Bacillus 

 pyocyaneus, and keep them at 3 8 '5 C., until there is a 

 copious growth over the whole surface of the agar-agar. 



(2) Into each tube pour 5 cc. of a *5 per cent solution 

 of caustic potash. 



(3) With a stout platinum needle carefully scrape the 

 culture off the surface of the agar-agar into the caustic 

 potash. 



(4) Collect the caustic potash emulsions thus made in a 

 glass mortar, and gently, but thoroughly, rub the mass up. 



(5) Pour the emulsion into a beaker, and digest it in a 

 water bath at 45 C., till it is liquid. 



(6) Filter this through a small Berkefeld filter. 



(7) To the filtrate add dilute hydrochloric acid, as long 

 as a precipitate appears. 



