is.
The statement that a crystal of calc-spar consists of carbonate of lime is
quite true, if we only mean that, by appropriate processes, it may be
resolved into carbonic acid and quicklime. If you pass the same carbonic
acid over the very quicklime thus obtained, you will obtain carbonate of
lime again; but it will not be calc-spar, or anything like it. Can it,
therefore, be said that chemical analysis teaches nothing about the
chemical composition of calc-spar? Such a statement would be absurd; but
it is hardly more so than the talk one occasionally hears about the
uselessness of applying the results of chemical analysis to the living
bodies that have yielded them.

One fact, at any rate, is out of reach of such refinements, and this is,
that all the forms of protoplasm which have yet been examined contain the
four elements, carbon, hydrogen, oxygen, and nitrogen, in very complex
union, and that they behave similarly toward several reagents. To this
complex combination, the nature of which has never been determined with
exactness, the name of protein has been applied. And if we use this term
with such caution as may properly arise out of our comparative ignorance
of the things for which it stands, it may be truly said that all
protoplasm is proteinaceous; or, as the white, or albumen, of an egg is
one of the commonest examples of a nearly pure protein matter, we may say
that all living matter is more or less albuminoid.

Perhaps it would not yet be safe to say that all forms of protoplasm are
affected by the direct action of electric shocks; and yet the number of
cases in which the contraction of protoplasm is shown to be effected by
this agency increases every day.

Nor can it be affirmed with perfect confidence that all forms of
protoplasm are liable to undergo that peculiar coagulation at a
temperature of from 40 to 50 degrees Centigrade, which has been called
"heat-stiffening"; though Kuhne's beautiful researches have proved this
occurrence to take place in so many and such diverse living beings, that
it is hardly rash to expect that the law holds good for all.

Enough has, perhaps, been said to prove the existence of a general
uniformity in the character of the protoplasm, or physical basis of life,
in whatever group of living beings it may be studied. But it will be
understood that this general uniformity by no means excludes any amount of
special modifications of the fundamental substance. The mineral, carb