388 



evaporated down and again precipitatrd, but only a \-eiy small quantit}' of gum 

 was again obtained. The amount of air-dried gum from the 400 grams of oleo- 

 resin was 9 grams; a further 0-5 gram was afterwards obtained from the residue 

 after the resin had been removed, making the total amount c)-5 grams, or z-^j 

 per cent. The ginn is thus shown to be present in a considerably less amount 

 than in the latex of Araucaria Cunninghamii. 



The air-dried ginn was again dissolved in water, and the dark-coloured 

 turbid solution agitated with alumina cream ; the liltrate was evaporated down 

 and again precipitated by alcohol and spread on the glass as before. This gum 

 precipitate on drying was still slightly coloured, indicating that owing to the 

 comparati\'el\' large amount present, the complete alteration of the inorganic 

 constituents had not taken place during the first drying. On again repeating the 

 process the gum was obtained colourless, as with the gum of Araucaria Cunning- 

 hamii. This purified gum was similar to the substance obtained from 

 Araucaria CHnninghamii, and had all the properties of gum arabic, was odourless 

 and tasteless, and had marked adhesive properties. The air-dried gum contained 

 14-9 per cent, of moisture, and gave 2-6 per cent, of ash, which consisted principally 

 of the carbonates of lime and magnesia. When heated with nitric acid in the 

 usual way, mucic acid was formed to the extent of 19 per cent., calculated on the 

 air-dried gum. A well marked manganese reaction was obtained with the ash of 

 the black gum, and also with the ignited alumina-cream precipitate, but was not 

 obtained vnth. the ash of the purified gum. Sufficient of the gum could not be 

 spared to determine the sugars formed by hydrolysis, but there is no reason to 

 suppose that this result would have been different from that obtained with the 

 gum of the latex of Araucaria Cunninghamii. 



The Reducing Sugar. 



After the gum had been finally precipitated, the filtrate was evaporated 

 down to expel the alcohol, water added, and the solution clarified; it was then 

 made up to 200 c.c. and filtered. This solution was titrated with Fehling's solution, 

 and 4 c.c. equalled -05 gram glucose. The 400 grams of oleo-resin, therefore, 

 contained 0-62 per cent, of reducing sugars. 



The RiiSiN. 



The solidified resin in the fiask was dried as much as possible, and treated 

 with ether until practically the whole of the resin had been dissolved. The resin 

 at this stage was very soluble in ether, and went readily into solution. The ether 

 solution of the resin was filtered, evaporated to dryness, ami the icsiii lualdl on 

 the water bath in thin layers until ail the ether had been r( iiidxcd. As llnis obiaiiud 

 the dried resin was somewhat soft, was light amber colouicd, and distinctly 

 darker in colour than the resin from the latex of Araucaria Cunninghamii obtained 



