visitations. It may be well that the general, as well as the
professional, public should have a sufficient knowledge of biological
truths to be able to take a rational interest in the discussion of such
problems, and to see, what I think they may hope to see, that, to those
who possess a sufficient elementary knowledge of Biology, they are not
all quite open questions.

Let me mention another important practical illustration of the value of
biological study. Within the last forty years the theory of agriculture
has been revolutionised. The researches of Liebig, and those of our own
Lawes and Gilbert, have had a bearing upon that branch of industry the
importance of which cannot be overestimated; but the whole of these new
views have grown out of the better explanation of certain processes
which go on in plants; and which, of course, form a part of the
subject-matter of Biology.

I might go on multiplying these examples, but I see that the clock won't
wait for me, and I must therefore pass to the third question to which I
referred: Granted that Biology is something worth studying, what is the
best way of studying it? Here I must point out that, since Biology is a
physical science, the method of studying it must needs be analogous to
that which is followed in the other physical sciences. It has now long
been recognised that, if a man wishes to be a chemist, it is not only
necessary that he should read chemical books and attend chemical
lectures, but that he should actually perform the fundamental
experiments in the laboratory for himself, and thus learn exactly what
the words which he finds in his books and hears from his teachers, mean.
If he does not do so, he may read till the crack of doom, but he will
never know much about chemistry. That is what every chemist will tell
you, and the physicist will do the same for his branch of science. The
great changes and improvements in physical and chemical scientific
education, which have taken place of late, have all resulted from the
combination of practical teaching with the reading of books and with the
hearing of lectures. The same thing is true in Biology. Nobody will ever
know anything about Biology except in a dilettante "paper-philosopher"
way, who contents himself with reading books on botany, zoology, and the
like; and the reason of this is simple and easy to understand. It is
that all language is merely symbolical of the things of which it treats;
the more complicat