nevitable limitation they still serve as luminous and
comprehensive guides to the subjects of which they treat. There is no
doubt but that if he had been a younger man when the new technical
methods made their appearance, he would have adopted them and their
results in his volumes. One of the first great pieces of work which
utilised methods more like those now used in all laboratories than
those employed during the greater part of Huxley's life as a teacher
was the classical investigation by Van Beneden into the changes in the
egg of Ascaris which accompany the process of fertilisation. When
Huxley read the memoir he exclaimed, "All this by the use of glacial
acetic acid--is it possible!" At once, Professor Howes relates, he
repeated the whole investigation himself, and, when satisfied,
declared that the "history of the histological investigation of the
future would be the history of its methods." Not only have the
chemical substances used in preparing tissues for examination greatly
increased since Huxley's time as an active worker, but a very
important method of investigation has come into general use. In
Huxley's time tissues or animals too large or too opaque to be
examined microscopically as whole structures were either teased by
needles or were cut with a razor by hand into comparatively thick
slices. The process of cutting, however practised the operator, was
tedious and uncertain, and it was almost impossible to cut a piece of
tissue into a series of thin slices without losing or destroying
considerable portions. Microtomes, with various accessory mechanical
appliances, have now been invented, and by means of these not only are
slices of great tenuity made with ease, but there is little difficulty
in cutting the most delicate organism into a ribbon of consecutive
slices. Such new methods have made almost a revolution in the study of
zooelogy, particularly of the lower forms of life and of the embryonic
stages of higher animals, and books written before these methods
became common have naturally been superseded.

Huxley did far more for the teaching of science than the preparation
of books, however useful these were. He was the practical inventor of
the laboratory system of teaching zooelogical science, and all over the
world the methods invented by him have been adopted in university
laboratories and technical schools. He had always declared that since
zooelogy was a physical science, the method of studying it