360 BACTEE^IOLOGICAL CHEMISTRY 



obtained from human tubercle bacilli which gives precipi- 

 tin reactions with the sera of tuberculous patients and 

 with antisera to the organism. The complex mixture of 

 polysaccharides from the bovine tubercle bacillus contains 

 much more inactive carbohydrate than does that from 

 human tubercle bacillus. An inactive carbohydrate, 

 precipitated by 80 per cent, acetic acid, is common to 

 both human and bovine bacilli ; another, which is soluble 

 in 96 per cent, acetic acid, occurs in bovine strains only. 

 The acetic acid soluble carbohydrate from human strains 

 is serologically active. The inactive carbohydrates from 

 bovine tubercle bacilli are strongly dextro-rotatory and 

 contain phosphorus but little or no pentose. The sero- 

 logically active polysaccharides contain t^-arabinose. The 

 wax fraction of the human tubercle bacillus (see p. 375) 

 contains fatty acids esterified by a specific polysaccharide 

 which gives precipitin reactions with anti -tubercle sera. 

 On hydrolysis it yields mannose, f?-arabinose and galac- 

 tose, with small amounts of inositol and glucosamine. 

 Two polysaccharides have been separated from the 

 attenuated tubercle organism, Bacille de Calmette-Guerin 

 (B.C.G.). Polysaccharide A, soluble in water, has 

 [«]D-f77*4°, and, on hydrolysis, gives 77 per cent, of 

 reducing sugar containing mannose, arabinose and 

 inositol, with 3 per cent, of an amino -sugar. The other 

 polysaccharide, insoluble in water but soluble in acids, is 

 a complex of about equal weights of a polysaccharide 

 (giving 95 per cent, of reducing sugars on hydrolysis) and 

 calcium phosphate. 



Sal. typhimurium has been investigated by three 

 methods which have given almost identical results. If 

 smooth strains of the organism are extracted with dilute 

 trichloracetic acid a polysacchride is removed which can 

 be recovered by dialysis, concentration and precipitation 

 by acetone. It is toxic to mice, is antigenic and reacts 

 specifically with the corresponding antisenim. On treat- 

 ment with hot dilute acetic acid it yields four components 



