Eleven-twelfths of the
latter were sugar.
That the birch readily yields its sap when the wood is wounded is well
known. Philipps, quoted by Sowerby, says:
"Even afflictive birch,
Cursed by unlettered youth, distills,
A limpid current from her wounded bark,
Profuse of nursing sap."
And that birch sap contains sugar is known, the peasants of many
countries, especially Russia, being well acquainted with the art of
making birch wine by fermenting its saccharine juice.
But I find no hourly or daily record of the amount of sugar-bearing
sap which can be drawn from the birch, or from any tree, before it
has acquired its great digesting or rather developing and transpiring
apparatus--its leaf system. And I do not know of any extended chemical
analysis of sap either of the birch, or other tree.
Besides sugar, which is present in this sap to the extent of 616
grains--nearly an ounce and a half--per gallon, there are present a
mere trace of mucilage; no starch; no tannin; 31/2 grains per gallon
of ammoniacal salts yielding 10 per cent. of nitrogen; 3 grains of
albuminoid matter yielding 10 per cent. of nitrogen; a distinct trace of
nitrites; 7.
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