aspect from the same branches of knowledge as they appeared fifty or
sixty years ago. It is not merely that the mass of observations in most
of these lines of study has enormously increased during this interval.
Were that all, the change could hardly be considered as an unmixed
benefit, because of the increased difficulty of assimilation of this
additional matter. Many would be the contradictions in the observations
and hopeless would be the task of bringing order out of such a chaos.
The advance in the several branches of knowledge has been largely one
resulting from improved methods of study, rather than one following
simply from diligence in the application of the old ways.

Let us turn to chemistry for our illustration of this. The chemistry of
the last century and the early decades of this was largely a descriptive
science, such as the natural history branches, zoology, and botany are
still in great part. Reasonably exact mineral analyses were made, it is
true, but the laws of chemical combination and the fundamental
conceptions of atoms and molecules had not been as yet generally
established. Now, this want of comprehensive views of chemical
reactions, their why and wherefore, was bad enough as it affected the
study of inorganic and metallic compounds, but what must have been the
conditions for studying the complex compounds of carbon, so widely
spread in the vegetable and animal kingdoms. Their number is so enormous
that, in the absence of any established relationships, not much more
than a mere enumeration was possible for the student of this branch of
chemistry. It is only within the last twenty years that chemists have
attained to any comprehensive views at all in the domain of organic
chemistry. It has been found possible to gradually range most carbon
compounds under two categories, either as marsh-gas or as benzol
derivatives, as fatty compounds or as aromatic compounds. To do this,
methods of analysis very different from those used in mineral chemistry