o teach their
several branches, but to elevate the whole standard of teaching.

I may speak with less restraint of those gentlemen who have aided me in
the most laborious part of my daily duties, the Demonstrators, to whom
the successive classes have owed so much of their instruction. They rise
before me, the dead and the living, in the midst of the most grateful
recollections. The fair, manly face and stately figure of my friend,
Dr. Samuel Parkman, himself fit for the highest offices of teaching, yet
willing to be my faithful assistant in the time of need, come back to
me with the long sigh of regret for his early loss to our earthly
companionship. Every year I speak the eulogy of Dr. Ainsworth's patient
toil as I show his elaborate preparations: When I take down my "American
Cyclopaedia" and borrow instruction from the learned articles of Dr.
Kneeland, I cease to regret that his indefatigable and intelligent
industry was turned into a broader channel. And what can I say too
cordial of my long associated companion and friend, Dr. Hodges, whose
admirable skill, working through the swiftest and surest fingers that
ever held a scalpel among us, has delighted class after class, and
filled our Museum with monuments which will convey his name to unborn
generations?

This day belongs, however, not to myself and my recollections, but to
all of us who teach and all of you who listen, whether experts in
our specialties or aliens to their mysteries, or timid neophytes just
entering the portals of the hall of science. Look in with me, then,
while I attempt to throw some rays into its interior, which shall
illuminate a few of its pillars and cornices, and show at the same time
how many niches and alcoves remain in darkness.

SCIENCE is the topography of ignorance. From a few elevated points we
triangulate vast spaces, inclosing infinite unknown details. We cast the
lead, and draw up a little sand from abysses we may never reach with our
dredges.

The best part of our knowledge is that which teaches us where knowledge
leaves off and ignorance begins. Nothing more clearly separates a vulgar
from a superior mind, than the confusion in the first between the little
that it truly knows, on the one hand, and what it half knows and what it
thinks it knows on the other.

That which is true of every subject is especially true of the branch of
knowledge which deals with living beings. Their existence is a perpetual
death and reanimatio