364 



BACTERIOLOGICAL CHEMISTRY 



and iiitrugen. Tlieir <-hief properties are given' in 



The polysaccharide from the smooth organisms is precipi- 

 tated by barium hydroxide, whilst that from the rough 

 variant is not. 



The streptococci afford both serologically active and 

 inactive polysaccharides. The former, obtained from 

 Str. salivarius by Lancefield, is a hapten, reacting with 

 homologous antisera but being non-antigenic. The 

 inactive polysaccharide, [a],)-73°, obtained from mucoid 

 hsemolytic streptococci of Lancefield's Group A, contains 

 no phosphorus, sulphur or amino -nitrogen. It contains 

 8-7 per cent, of nitrogen, 11 per cent, of acetyl group and 

 46 per cent, of uronic anhydrides ; it has an acid equiva- 

 lent of 380. It is an acetyl-glucosamine -glucuronic acid 

 complex, apparently identical with or closely related to 

 the hyaluronic acid in bovine vitreous humour, since it is 

 hydrolysed by the autolytic enzyme of the pneumococcus 

 (see p. 358). A group specific polysaccharide has been 

 extracted from the organisms with formamide and 

 contains 1-72 per cent, of nitrogen, 0-7 per cent, of 

 phosphorus and has [a]D-71-5°. It contains glucos- 

 amine and uronic acid residues. It reacts at a dilution of 

 1 in 2x10*^ with homologous antisera. 



The Vibrios have been divided into six groups by 

 Linton on the basis of their content of proteins and poly- 

 saccharides. Those derived from cholera patients, Group 

 I, form a polysaccharide which on hydrolysis yields 



