546 BACTERIAL ORIGIN OF GUMS OF ARABIN GROUP, 



which had been treated with phosphoric acid, melted at IGS-IGO"". 

 Both osazones were put together and dissolved in weak alcohol. 

 The alcohol was boiled off and a water-insoluble, lemon-yellow, 

 crystalline powder which melted at 19 V was obtained. From 

 the hot water solution crystals separated out on cooling; these 

 dried on porcelain as a brownish-yellow skin which melted at 

 170'^, The appearances and melting points of these osazones 

 indicated galactosazone, and a mixture of arabinosazone and 

 galactosazone. 



As the quantities of sugars obtained by the above methods had 

 been too small to enable the osazones to be separated in a prac- 

 tically pure state, a further quantity of gum was hydrolysed. 

 This test differed from the former in the gum having been obtained 

 in fluid media containing saccharose. The possibility of agar 

 contaminating the gum was thus prevented. The carbohydrate was 

 freed from saccharose and reducing sugars by repeated precipitation 

 with alcohol from aqueous solution or suspension. The curdy gum 

 finally obtained was moistened with 2 c.c. of strong sulphuric acid 

 and was then rubbed into a paste in a glass mortar. When the 

 mixture had become brownish in colour, 25 c.c. of water were 

 added, and, after transferring to a flask, the mixture w^as boiled 

 for 9 hours under a reflux condenser. The solution, which con- 

 tained reducing sugars, was neutralised with barium carbonate, 

 filtered, evaporated, clarified with aluminium hydrate and finally 

 treated with phenylhydrazine mixture"^ and heated on the 

 water-bath for two hours. The solution was cooled and the 

 residue, after filtration, was dried on porcelain and then treated 

 with ether to extract the tarry impurity. The osazones melted 

 at 175-177"'\ 



The undoubted mixture of osazones was successively treated 

 with (1) hot water, (2) hot dilute alcohol, and (3) hot strong 

 alcohol. The first fraction consisted of a mass of yellow crystalline 

 needles which dried on porcelain as a brown skin and melted at 

 162-164'^. Further treatment with hot water extracted arabin- 



* Phenylhydrazine 1 c.c, glacial acetic acid 1 c.c, water 0*5 c.c 



