ed the things, the more bare is the symbol, and the
more its verbal definition requires to be supplemented by the
information derived directly from the handling, and the seeing, and the
touching of the thing symbolised:--that is really what is at the bottom
of the whole matter. It is plain common sense, as all truth, in the long
run, is only common sense clarified. If you want a man to be a tea
merchant, you don't tell him to read books about China or about tea, but
you put him into a tea-merchant's office where he has the handling, the
smelling, and the tasting of tea. Without the sort of knowledge which
can be gained only in this practical way, his exploits as a tea merchant
will soon come to a bankrupt termination. The "paper-philosophers" are
under the delusion that physical science can be mastered as literary
accomplishments are acquired, but unfortunately it is not so. You may
read any quantity of books, and you may be almost as ignorant as you
were at starting, if you don't have, at the back of your minds, the
change for words in definite images which can only be acquired through
the operation of your observing faculties on the phenomena of nature.

It may be said:--"That is all very well, but you told us just now that
there are probably something like a quarter of a million different kinds
of living and extinct animals and plants, and a human life could not
suffice for the examination of one-fiftieth part of all these." That is
true, but then comes the great convenience of the way things are
arranged; which is, that although there are these immense numbers of
different kinds of living things in existence, yet they are built up,
after all, upon marvellously few plans.

There are certainly more than 100,000 species of insects, and yet
anybody who knows one insect--if a properly chosen one--will be able to
have a very fair conception of the structure of the whole. I do not mean
to say he will know that structure thoroughly, or as well as it is
desirable he should know it; but he will have enough real knowledge to
enable him to understand what he reads, to have genuine images in his
mind of those structures which become so variously modified in all the
forms of insects he has not seen. In fact, there are such things as
types of form among animals and vegetables, and for the purpose of
getting a definite knowledge of what constitutes the leading
modifications of animal and plant life, it is not needful to examine
mo