NOTES ON ALKALOIDS AND OTHER SUBSTANCES. 
45 
the subject. I have only endeavoured to collect together such 
facts as were scattered in chemical literature, and to explain them 
as untechnically as was possible with due regard to exactness and 
truth. This must be my apology if to some I seem too elementary, 
and to others too abstruse. 
Assuming that all plants are built up of cells, and that the 
essential parts of a cell are the cell-wall, and the cell contents (or 
protoplasm), we may assert that the cell-wall mainly consists of 
one of the varieties of cellulose, a colorless, tasteless substance 
insoluble in water, existing in three forms — Cellulose proper, as 
found in cotton ; paracellulose, existing in some roots and the 
epidermis of leaves ; and metacellulose or fungin, occurring in fungi 
and lichens. These are distinguished by different solubilities in 
ammoniated copper solution. 
The cell-wall of fungi consists then of this metacellulose or 
fungin. They contain no lignin or woody fibre. All varieties of 
cellulose have the composition Cg Og, or a multiple of it. 
The cell-contents, on the other hand, are very complex. Of 
course there is water, varying from 90 per cent., in fleshy species, 
to 9 per cent, in a woody Polyporus. Also essential to life is some 
variety of fibrin or albumen ; substances classed together under the 
name of “ albuminoids,” and distinguished by containing nitrogen 
as well as carbon, hydrogen and oxygen, by their complicated con- 
stitution, and the ready changes they undergo under the action of 
vital forces or of putrefaction. As these substances are especially 
valuable in food, the nutritive value is in great part indicated by 
the percentage of nitrogen. This percentage in fungi is very high, 
higher indeed in dried Agarics than in peas and beans, the next 
articles in this respect. As to the special kinds of albuminoids 
present in fungi, this has not been made out, but we know that 
they closely resemble the varieties found in animal food. 
Mineral Salts, found as “ ash ” on burning, are also essential in 
food. The cells of fungi contain a large proportion. Analyses by 
Schlossberger and Popping show amounts of nitrogen varying from 
7’2 per cent, in A. (Psalliota) arvensis, to 3‘2 in Cantharellus 
cibarius ; and an “ ash,” or mineral matter, varying from 19 '8 per 
cent, in Psalliota arvensis, to 3’0 in Polyporus fomentarius, all cal- 
culated on the dried plant. 
Another class of substances containing nitrogen are “alkaloids,” 
or organic bases. These do not afford nutriment, but are cha- 
racterised by poisonous or medicinal action. They are generally 
present in very small quantities. We will defer their consideration 
for the present. 
Starch and chlorophyll, two prominent constituents of other 
vegetals, are absent in fungi, but a near relative of the former, 
Myco-inulin, closely resembling the inulin found in Dahlia roots, 
&c., has been discovered in a kind of truffle, Elaphomyces granula- 
tus. It is a white, tasteless substance, soluble in hot water, and 
not blued by iodine. Its formula is Cg Og. 
