836 THE GUM AND BYPRODUCTS OF BACTEllIUM SACCIIARI, 



emulsion was then heated in the autoclave at a pressure of three 

 atmospheres for fifteen minutes. This treatment produced a 

 separation of the slime into a comparatively clear supernatant 

 liquid and a sediment. The sediment was treated with water 

 and again heated in the autoclave. The second heating had 

 apparently brought all the remainder of the gum into solution, 

 for the insoluble matter was not at all slim3\ The gum solutions 

 were clarified with a little aluminium hydrate and, after filtration, 

 concentrated by evaporation. About 100 c.c. of a thick, viscous, 

 transparent gum mucilage were obtained. This was adhesive, 

 and firmly fastened paper to glass. 



Upon testing drops of the thick gum mucilage with drops of 

 reagents upon a glass plate as recommended by Maben,* basic 

 lead acetate and ammoniacal lead acetate gave white curd}' masses, 

 ferric chloride gave a translucent brownish clot, barium hydrate 

 thickened the mucilage, Schweitzer's reagent produced a gela- 

 tinous slime, dilute iodine gave a reddish tinge; no reactions 

 were obtained with borax paste, copper sulphate, neutral lead 

 acetate, milk of lime, aluminium hydrate, potassium hydrate, or 

 sodium silicate. The precipitation with lime water was not con- 

 firmed. Copper sulphate followed by potassium hydrate gave a 

 gelatinous blue precipitate which contracted to a curdy mass 

 upon boiling Fehling's solution under similar conditions gave 

 no coagulation — a point wherein the gum differs from many 

 others, e.g., yeast gums.f 



A portion of the gum was boiled with 5 % sulphuric acid for 

 five hours, when portions showed, upon being tested, the absence 

 of gum and the presence of reducing sugars. After removal of 

 the sulphuric acid by barium hydrate, the osazones of the sugars 

 were prepared. They were obtained fractionally by the repeated 

 addition of phenylhydrazine acetate solution followed b}' heating 

 on the water-bath. Three fractions were obtained. These were, 



* Jouin. Pharm. xx., 719. 

 t Lafar, Technical Mycology, ii. , 1, 178. 



