338 BACTERIOLOGICAL CHEMISTRY 



synthesis must be initiated l)y the desoxyribonucleic 

 acid. The conversion only occurs with actively growing 

 cultures and not in resting suspensions. The desoxyribo- 

 nucleic acid appears to be autocatalytic since the new 

 Smooth organisms, even after repeated subcultures, 

 contain it in much greater amount than that added to 

 stimulate the change. This is analogous to the propaga- 

 tion of the tobacco mosaic virus, when injected into the 

 plant. 



The capsular substance of B. anthracis, apparently 

 identical with that of B. 7nesentericus, which reacts with 

 antisera in very high dilution, on hydrolysis with acid 

 loses it serological activity and forms d{ — ) -glutamic acid. 

 This is the first recorded natural occurrence of the Isevo- 

 rotatory isomer of glutamic acid. It is suggested that the 

 capsular substance has a polypeptide -like structure : — 



CO.CH.NH2(CH2)2COOH 



COOH NH 



L 



[.NH.— [CO.CH.(CH2)2COOH] ^. 



COOH 



or 



COOH CO.(CH2)2CH.NH2.COOH. 



CH.NH— [CO.(CH2)2.CH.NH.COOHJ ^ 



I 

 COOH 



Protein Synthesis. — The synthesis of proteins by 

 micro-organisms has been most extensively studied in the 

 case of the yeasts. The yeast proteins, constituting 

 approximately 50 per cent, of the dry weight of the 

 organism, are valuable as a food since they contain all 

 the known amino-acids. Beer yeasts have been used as 

 a cattle fodder and even for human consumption, but 



