quantity, Grapes act freely on the kidneys, and
promote a flow of urine. The vegetable acids of the fruit become
used up as such, and are neutralised in the system by combining
with the earthy salts found therein, and they pass off in the urine as
alkaline carbonates. With full-blooded, excitable persons, grapes in
any quantity are apt to produce palpitation, and to quicken the
circulation for a time. Also with persons of slow and feeble
energies, having a languid digestion (and especially if predisposed
to acid fermentation in the stomach), Grapes are apt to disagree.
They send their glucose straightway into the circulation combined
with acids found in the stomach, and create considerable distress of
heartburn and dyspepsia. "Thus," says Dr. King Chambers, "is
generated acidity of the stomach, parent of gout, and of all its
hideous crew." Likewise wine, especially if sweet, new, or
full-bodied, when taken by such persons at a meal, is absorbed but
slowly by the stomach, and much of the sugar, with some alcohol,
becomes converted by fermentation into acetic acid, which further
causes the oily ingredients in the food which has been swallowed to
turn rancid. "Things sweet to taste prove to digestion sour." But
otherwise, with a person in good health, and not given to gout or
rheumatism, Grapes are an excellent food for supplying warmth as
combustion material, by their ready-made sugar; whilst the essential
flavours of the fruit are cordial, and [239] whilst a surplus of the
glucose serves to form fat for storage.

What is known as the _Grape-cure_, is pursued in the Tyrol, in
Bavaria, on the banks of the Rhine, and elsewhere--the sick person
being ordered to eat from three to six pounds of grapes a day. But
the relative proportions of the sugar and acids in the various kinds
of grapes have important practical bearings on the results obtained,
determining whether wholesome purgation shall follow, or whether
tonic and fattening effects shall be produced. In the former case,
sufferers from sluggish liver and torpid biliary functions, with
passive local congestions, will benefit most by taking the grapes not
fully ripe, and not completely sweet; whilst in the latter instance,
those invalids will gain special help from ripe and sweet grapes,
who require quick supplies of animal heat and support to resist rapid
waste of tissue, as in chronic catarrh of the lungs, or mucous catarrh
of the bowels.

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