s 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, nor 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 which 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 towards 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
proteine 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 affected 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 40-50 degrees centigrade, which has been called
"heat-stiffening," though Kuhne's [101] 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, carbonate of lime, assumes an immense diversity