had to be applied. The mere finding out of percentage composition tells
us little or nothing about an organic compound. What the elements are
that compose the compound is not to be found out. That can be told
beforehand with almost absolute certainty. What is wanted is to know how
the atoms of carbon, hydrogen, oxygen, and nitrogen are linked together,
for, strange to say, these differences of groupings, which may be found
to exist between these three or four elements, endow the compounds with
radically different properties and serve us as a basis of
classification.

The development of this part of chemistry, therefore, required very
different methods of research. Instead of at once destroying a compound
in order to learn of what elements it was composed, we submit it to a
course of treatment with reagents, which take it apart very gradually,
or modify it in the production of some related substance. In this way,
we are enabled to establish its relations with well defined classes and
to put it in its proper place. Of equal importance with the analytical
method of study, however, is the synthetical. This method of research,
as applied to organic compounds, embodies in it the highest triumphs of
modern chemistry. It has been most fruitful of results, both theoretical
and practical. Within recent years, hundreds of the products of
vegetable and animal life have been built up from simpler compounds.
Thousands of valuable dye-colors and other compounds used in the arts
attest its practical value. It may, therefore, seem anomalous when I say
that one of the most important of all the classes of organic compounds
has not shared in this advance. The alkaloids, that most important class
from a medical and pharmaceutical point of view, have until quite
recently been defined in the books simply as "vegetable bases,
containing nitrogen." Whether they were marsh-gas or benzol derivatives
was not made out; how the four elements, carbon, hydrogen, oxygen, and