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, 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.
Pages:
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167