Atkins and Sherrard — The Figments of Fruits. 333 



These solubilities at once differentiate the Capsicum pigments from the 

 other three. Owing to the small quantities available, it was not possible to 

 measure the solubilities with accuracy. Before extracting with the organic 

 solvents, the fruits were boiled with water till they gave scarcely any tinge of 

 colour to it. The chocolates gave a yellow-brown aqueous extract, and the 

 reds gave either scarcely any colour or a clear yellow. The addition of a 

 little sodium carbonate to the latter neutralized the faintly acid reaction of 

 the solution, and greatly intensified the colour. These water-soluble pigments 

 may possibly be due to disintegration changes in the plastids, but it seems 

 equally likely that they are quite separate substances, as it was possible to 

 remove them almost completely by repeated extraction at the boiling point. 

 The latter view is borne out by the fact that an alcoholic solution of the red 

 fruit, made after prolonged aqueous extraction, when allowed to evaporate 

 slowly in the dark, gave a light red brown ring on the side of the beaker, 

 whilst a light yellow spot was left on the bottom. 



Attempts were made to ascertain whether the pigments were mixtures, by 

 extracting the fruits with one solvent after another. Thus chocolates gave a 

 very dark brown to cold acetone, a lighter and somewhat redder brown to 

 cold pyridine, and to cold benzene a still lighter brown. It was, however, 

 found that the acetone solution could be exactly matched with the benzene 

 by suitable dilution. The pyridine employed became slightly coloured on 

 standing, and its solution could not be matched with the acetone or benzene, 

 possibly because of the colour of the solvent. Alcohol, too, gave a light 

 yellow-green. This could not be matched with any of the above. 



Extraction of the chocolates with petroleum ether (b. p. 40'"'-60°) afforded 

 a bright yellow solution, varying with concentration to yellow-brown which 

 could not be matched with the reddish alcoholic extract. The latter was 

 always of a redder hue. The acetone extract was very similar in colour to 

 that made with petroleum ether. By evaporating the alcoholic solution, 

 however, and dissolving the residue in petroleum ether, it was found that the 

 solution was quite similar to that extracted by the latter directly. Accord- 

 ingly it must be concluded that the difference in colour is only due to an effect 

 produced by the solvent, as in the well-known instance of iodiue solutions. 



Extraction of red fruits with cold solvents gave the following results : — 



Pyridine, bright red solution. ■ \ . „ , 



•^ ^ X All exactly 



Alcohol (absolute) | lighter red, yellower I jj^j^^gj^g^j q,j 



^'''^"^^ ( *""^§^^- dilution. 



Benzene, yellow-red, like bichromate solution. 



The evidence here, as far as it goes, is that the red is one pigment. 



