CONSTITUENTS 85 



and beans. The special kinds of albuminoids are not deter- 

 mined, but they closely resemble those found in animal food. 

 The cell walls consist of meta-cellulose or fungin, but there is 

 no lignin or woody fibre. Some gummy substance and oil or 

 fat occur in most species. Mineral salts are found as ash on 

 burning. The ash or mineral matter varies from 19 - 8 in 

 Psalliota arvensis to 3"0 in Forties fomentarius, calculated on 

 the dried plant. 



Vegetable acids of various kinds have been named in con- 

 nection with Fungi, as citric acid, malic acid, fumaric acid, 

 oxalic acid — Hamlet and Plowright found - 083 per cent in 

 Fistulina hepatica — and oxalate of lime or potassium is by no 

 means uncommon. 1 Agaricic acid has been found in Polyporus 

 officinalis. Other acids of a special nature may be found in 

 particular species. Some Fungi contain free acetic acid. A 

 substance called Fungic acid is mentioned by earlier observers, 

 but this is stated to be a mixture of citric, malic, and phos- 

 phoric acids. 



The colouring matters of Fungi are still open to investiga- 

 tion, and especially so by the aid of the spectroscope. By this 

 means four yellow or orange matters have been determined — 

 phycoxanthine, which is yellow ; pezisaxanthine, which is the 

 orange colour of Feziza aurantia; and two colours related to 

 xanthophyll, or the yellow colouring matter of leaves. Phip- 

 son obtained a red colouring matter from Gortinarius violaceus, 

 and Stahlschmidt a substance which constituted 43 - 5 per cent 

 of the dried Fungus, from what is supposed to have been Poria 

 purpurea. This substance has been termed " polyporic acid," 

 and is soluble in alkalis, with an intense violet colour. Certain 

 species of Boleti, notably Boletus lurialus, contain a yellow 

 colouring matter which becomes blue on exposure to the air. 

 Phipson asserted that this was a derivative of aniline, although 

 neither aniline nor its salts have this property. Stewart 2 

 suggested that indigogen was a yellowish substance which is 



1 Crystals of oxalate of lime may often be seen upon the surface of the pileus 

 of Polyporus sulfureus. Oxalic acid in some form has been detected in scores of 

 species of Hymenomycetes. Hamlet and Plowright mention a, great number 

 {Journ. Chem. Soc, 1877). 



2 Stewart, Alkaloids in Fungi. Trans. Woolhope Club (1883), p. 119. 



