must needs
be analogous to that which is followed in other physical sciences. If
a man wishes to be a chemist, it is necessary not only 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 reads in his
books and hears from his teachers, mean. "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 great
and obvious difficulty in the practical teaching of biology appeared
to be the immense number of different kinds of animals and plants in
existence. A human life would not suffice for the examination of a
hundredth part of these. Huxley met the difficulty by the "type"
system.

"There are certainly more than 100,000 species of insects, and
yet anyone who knows one insect, if a properly chosen one, will
be able to have a fair conception of the structure of the whole.
I do not mean to say he will know that structure thoroughly, or
as well as is desirable that 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 these 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 more than a
comparatively small number of animals and plants."

The type system in itself was not absolutely new. Rolleston, the
Linacre professor at Oxford, in his _Forms of Animal Life_ had
devised the method of teaching comparative anatomy by the study of a
graded series of animals. But his method depended on the existence of
a series of dissections and preparations made by a skilled craftsman;
the tradition of teaching by authority instead of by investigation was
maintained, although the authority of books and lectures was aided by
museum specimens in glass bottles, the actual basis of