with those terrible 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 over-estimated; 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.