the scholar takes a good deal on trust from a
teacher, who, knowing the facts by his own knowledge, can describe them
with so much vividness as to enable his audience to form competent ideas
concerning them. The system which I repudiate is that which allows
teachers who have not come into direct contact with the leading facts of
a science to pass their second-hand information on. The scientific
virus, like vaccine lymph, if passed through too long a succession of
organisms, will lose all its effect in protecting the young against the
intellectual epidemics to which they are exposed.

VII.

ON THE PHYSICAL BASIS OF LIFE.[10]

In order to make the title of this discourse generally intelligible, I
have translated the term "Protoplasm," which is the scientific name of
the substance of which I am about to speak, by the words "the physical
basis of life." I suppose that, to many, the idea that there is such a
thing as a physical basis, or matter, of life may be novel--so widely
spread is the conception of life as a something which works through
matter, but is independent of it; and even those who are aware that
matter and life are inseparably connected, may not be prepared for the
conclusion plainly suggested by the phrase, "_the_ physical basis or
matter of life," that there is some one kind of matter which is common
to all living beings, and that their endless diversities are bound
together by a physical, as well as an ideal, unity. In fact, when first
apprehended, such a doctrine as this appears almost shocking to common
sense.

What, truly, can seem to be more obviously different from one another in
faculty, in form, and in substance, than the various kinds of living
beings? What community of faculty can there be between the
brightly-coloured lichen, which so nearly resembles a mere mineral
incrustation of the bare rock on which it grows, and the painter, to
whom it is instinct with beauty, or the botanist, whom it feeds with
knowledge?

Again, think of the microscopic fungus--a mere infinitesimal ovoid
particle, which finds space and duration enough to multiply into
countless millions in the body of a living fly; and then of the wealth
of foliage, the luxuriance of flower and fruit, which lies between this
bald sketch of a plant and the giant pine of California, towering to the
dimensions of a cathedral spire, or the Indian fig, which covers acres
with its profound shadow, and endures while nations and empi