70 PROTEIN POISONS 



we have designated it, containing all the carbohydrates, 

 remains insoluble in this menstruum. 



Leach 1 has studied the carbohydrate in the haptophor 

 portion of the cellular substance of the colon bacillus. 

 Gram samples of the haptophor portion were dissolved in 

 water containing a little alkali, neutralized with hydro- 

 chloric acid to definite strength and heated on a water-bath 

 in a flask with a reflux condenser. The hydrolyzed solution 

 was neutralized and titrated with Fehling's solution. Al- 

 though there is undoubtedly some pentose present, there 

 is no proof that the reducing substance is all carbohydrate. 

 However, for purposes of comparison the reducing sub- 

 stance was calculated as xylose. In order to find conditions 

 giving the maximum yield, amount and strength of acid 

 as well as time of boiling were varied as shown in the 

 following table: 



REDUCING POWER OF COLON HAPTOPHOR 



Hours Per cent, calculated 

 as xylose. 



7.05 

 16.45 

 21.56 

 23 . 12 

 23 . 93 

 23.53 



As shown by these figures the maximum amount of 

 reducing substance was obtained by using 2.5 per cent, 

 acid, and boiling for three hours. Longer heating changes 

 the result very little. 



Attempts were made to separate this carbohydrate from 

 the other constituents of the haptophor of the colon bacillus. 

 A 5 per cent, aqueous solution of the haptophor was poured 

 into four volumes of absolute alcohol, containing 10 c.c. of 

 hydrochloric acid and 100 c.c. of ether per liter. After 

 settling, the supernatant liquid was siphoned off and the 

 precipitate (known as G) collected with suction, washed 



i Jour. Biol. Chem., 1907, iii, 443. 



