10 EXPERIMENT STATION RECORD. 



gave tlie anilin acetate reaction for pentose, but none for galactose. The pres- 

 ence of fructose and glucose in considerable amounts was quite definitely estab- 

 lished by several reactions characteristic of these sugars. 



"The dried mucilage of the prickly pear, when separated by precipitation 

 with alcohol from a 2 per cent solution, contained 15 per cent of galactan, 31 

 per cent of pentosan, and 12 per cent of ash. 



" The mucilage could not be separated completely from cell fragments, starch, 

 crystals of calcium oxalate, and other solid particles that caused opalescence 

 and turbidity. A dilute solution with 1.5 per cent of total soluble solid matter, 

 rendered fairly clear by repeated filtration through silk, had no effect on polar- 

 ized light. This was true of all the solutions of mucilage obtained in this work, 

 both before and after subjecting them to acid hydrolysis. . . . 



" Hydrolysis of the mucilage by digestion for several hours with 1.25 per 

 cent sulphuric acid solution produced a sugar that had properties similar to 

 arabinose. When its osazone was formed, oily globules rose to the surface. 

 The precipitate was darker than glucosazone, readily soluble in hot water, and 

 melted at near 160°. 



"A 95 per cent alcoholic extract of the dried stems, previously treated with 

 ether, contained a sugar with specific rotations made on three separate solu- 

 tions of — 6.6°, — 8.25°, and — 7.1°. The osazone produced from this sugar 

 had properties similar to those of glucosazone. These results indicate the pres- 

 ence of mixtures of glucose and fructose in this extract. 



"A 60 per cent alcoholic extract of the dried stems contained a substance 

 apparently intermediate in character between mucilage and sugars. It did not 

 reduce Fehling solution before hydrolysis, but was very readily hydrolyzed 

 by dilute acids. Alcohol stronger than 60 per cent reprecipitated this material 

 as a flocculent mass, quite different in appearance and properties from the 

 precipitate of the mucilage with alcohol. The precipitate was readily soluble 

 In water, but its solution was not mucilaginous. When hydrolyzed it gave a 

 plus rotation to polarized light. 



" The coloring matter can be concentrated and made into a marketable 

 product, of value for coloring certain foods, by first removing mucilages and 

 gums with alcohol, and precipitating the pigment from the filtrate with acetone. 



"The pigment lis evidently a glucosid. When separated from the juice with 

 alcohol and acetone, and then precipitated with lead acetate, the coloring 

 matter liberated by sulphuric acid gave a sugar on hydrolysis, with properties 

 similar to those of glucose. 



" The lead salt produced by precipitating the purified pigment with lead 

 acetate contains 61.42 per cent lead." 



A solution of the gum, while very viscous, possesses only a very low degree 

 of adhesiveness. 



The analysis and composition of grapes, R. Brunet {Bev. Vit., 37 {1912), 

 No. 9Ji2, pp. 15-20). — This is a discussion in regard to the variations in the 

 chemical composition of grapes during the cycle of growth. It includes analyses 

 of the stems, skin, pulp, and seeds. 



The composition of the apple as affected by irrigation, C. E. Bkadlet 

 (Jour. Itidus. and Engirt. Chem., 3 (19J1) No. 7, pp. J/OG, 497). — ^Apples which 

 were grown on irrigated soil were found to be somewhat higher in moisture, 

 higher in sugar, and lower in solids than the samples which were obtained 

 from the dry check plats. The apples were also larger, but the individual 

 apples from a given space showed very little variation among themselves. 

 The protein content of the peelings showed an average of 0.7 per cent and 

 that of the edible portion only 0.2 per cent. Traces of starch were present in 

 the samples tested. 



