Chemical Science. 407 



With regard to the vegeto-alkalies 13, 14, 15, 16, and 17, every pos- 

 sible care was taken to obtain them in a state of purity, and espe- 

 cially free the one from another. The occurrence of several of them 

 in conjunction rendered the latter precaution exceedingly necessary, 

 and the authors suggest that probably the discordant results already 

 published arise from some such mixture *. 



16. RESULTS OBTAINED FROM THE SEED OP THE MANGO. 



The mango tree (Mangifera Jndica^ L.) has been transported from 

 the East Indies to St. Domingo, and the other neighbouring islands, 

 where it is now exceedingly abundant. In consequence of which its 

 products may now find useful applications ; to forward which purpose 

 M. Arequin has devoted his attention to the analysis of the seed. 

 The fruit is a fine mass of pulp, very agreeable in the estimation of 

 some, and the seed or grain lies in the middle, having the form of a 

 kidney, and inclosed in a parchment-like integument. 



The mango pulp contains much crystallizable sugar, and also 

 citric acid and gum. 



The mango-seed is remarkable for the large quantity of gallic 

 acid present, and for the presence also of stearic acid, and for the 

 useful state of its starch. When a seed is cut with a knife, it gives 

 a deep blue colour to the latter ; when touched with persulphate of 

 iron, it acquires a fine blue colour, both effects due to the gallic acid 

 present. 



Five pounds and a half of the seeds being worked upon, by various 

 digestions in water, alcohol, &c, and subsequent evaporations gave 

 above eight ounces and a half of crystallized gallic acid. 



When the pulp of the seeds had been exhausted by water, it was 

 acted upon by alcohol, and a substance obtained by evaporation 

 from the alcoholic solutions, which crystallized, and had the follow- 

 ing properties : it was perfectly white ; was insipid and inodorous ; 

 it fused at 70 C. (158 Fahrenheit) -, on cooling, it crystallized in 

 mingling long acicular forms ; it dissolved in strong boiling alcohol, 

 in all proportions, the solution on cooling yielding mammellated 

 groups of acicular crystals; it is insoluble in water; it reddens 

 moistened litmus paper ; its solution in weak alcohol reddens infu- 

 sion of litmus ; it is quite soluble in oils and fatty bodies ; it unites 

 to salifiable bases, forming well characterized salts (soaps) ; when 

 made into a taper, it burns like wax, with a fine white flame. This 

 substance has all the physical and chemical characters of stearic 

 acid, which therefore exists, ready formed, in the vegetable kingdom. 

 Its quantity was rather more than two ounces. 



When the pulp, thus far exhausted, was treated with ether, a fatty 

 matter was obtained from it, fusing at 30 C. (86 Fahrenheit) ; 

 soluble in hot ether to any extent ; insoluble in rectified alcohol ; 

 liquefying in the mouth like cocoa butter ; when formed into a candle, 



* Journ. de Pharm., 1831, p. 437. 

 VOL. II. Nov. 1831. 2 E 



