eats belong to the class here indicated.
The watery particles are nearly or quite driven out from the meat, and
thus one of the three decomposing agents is rendered of no effect. In
some cases, the drying is not sufficient to produce the result,
without the aid of the remarkable antiseptic properties of salt;
because decomposition may commence before the moisture is quite
expelled. In many parts of the country, hams are hung within a
wide-spreading chimney, over or near a turf-fire, and where a free
current of air, as well as a warm temperature, may act upon them; but
the juices become dissipated by this rude process. Simple drying,
without the addition of salt or any condiment, is perhaps more
effectual with vegetable than with animal substances.

But it is under the third point of view that the preservative process
is more important and interesting, inasmuch as it admits of a far more
extensive application. We speak of the abstraction of _air_.
Atmospheric air affects dead organic matter chiefly through the agency
of the oxygen which forms one of its constituents; and it is
principally to insure the expulsion of oxygen that air is excluded.
The examples which illustrate the resulting effects are numerous and
varied. Eggs have been varnished so as to exclude air, and have
retained the vital principle in the chick for years; and it is a
familiar domestic practice, to butter the outside of eggs as a means
of keeping them. The canisters of preserved provisions, however, are
the most direct and valuable result of the antiseptic action by
exclusion of air. The Exhibition Jury on Class 3, in their Report on
this subject, speak thus warmly thereupon:--'It is impossible to
overestimate the importance of these preparations. The invention of
the process by which animal and vegetable food is preserved in a fresh
and sweet state for an indefinite period, has only been applied
practically during the last twenty-five years, and is intimately
connected with the annals of arctic discovery. The active measures
taken to discover a north-west passage, and to prosecute scientific
research, in all but inaccessible regions, first created a demand for
this sort of food; and the Admiralty stimulated the manufacturers to
great perfection in the art. As soon as the value of these
preparations in cold climates became generally admitted, their use was
extended to hot ones, and for the sick on board ship under all
circumstances. Hitherto they had