rough and scientific account was ever given of
the agencies which come into play in the manufacture of beer, of the
conditions necessary to its health, and of the maladies and
vicissitudes to which it is subject. Hitherto the art and practice of
the brewer have resembled those of the physician, both being founded
on empirical observation. By this is meant the observation of facts,
apart from the principles which explain them, and which give the mind
an intelligent mastery over them. The brewer learnt from long
experience the conditions, not the reasons, of success. But he had to
contend, and has still to contend, against unexplained perplexities.
Over and over again his care has been rendered nugatory; his beer has
fallen into acidity or rottenness, and disastrous losses have been
sustained, of which he has been unable to assign the cause. It is the
hidden enemies against which the physician and the brewer have
hitherto contended, that recent researches are dragging into the light
of day, thus preparing the way for their final extermination.

*****

Let us glance for a moment at the outward and visible signs of
fermentation. A few weeks ago I paid a visit to a private still in a
Swiss chalet; and this is what I saw. In the peasant's bedroom was a
cask with a very large bunghole carefully closed. The cask contained
cherries which had lain in it for fourteen days. It was not entirely
filled with the fruit, an air-space being left above the cherries when
they were put in. I had the bung removed, and a small lamp dipped
into this space. Its flame was instantly extinguished. The oxygen of
the air had entirely disappeared, its place being taken by carbonic
acid gas. [Footnote: The gas which is exhaled from the lungs after the
oxygen of the air has done its duty in purifying the blood, the same
also which effervesces from soda water and champagne.] I tasted the
cherries: they were very sour, though when put into the cask they were
sweet. The cherries and the liquid associated with them were then
placed in a copper boiler, to which a copper head was closely fitted.
From the head proceeded a copper tube which passed straight through a
vessel of cold water, and issued at the other side. Under the open
end of the tube was placed a bottle to receive the spirit distilled.
The flame of small wood-splinters being applied to the boiler, after a
time vapour rose into the head, passed through the tube, was condensed
by t