e the facts into your own hands; look, and see for
yourself!"--these were the maxims which Agassiz preached wherever he
went, and their effect on pedagogy was electric. The extreme rigor of
his devotion to this concrete method of learning was the natural
consequence of his own peculiar type of intellect, in which the
capacity for abstraction and causal reasoning and tracing chains of
consequences from hypotheses was so much less developed than the genius
for acquaintance with vast volumes of detail, and for seizing upon
analogies and relations of the more proximate and concrete kind. While
on the Thayer expedition, I remember that I often put questions to him
about the facts of our new tropical habitat, but I doubt if he ever
answered one of these questions of mine outright. He always said:
"There, you see you have a definite problem; go and look and find the
answer for yourself." His severity in this line was a living rebuke to
all abstractionists and would-be biological philosophers. More than
once have I heard him quote with deep feeling the lines from Faust:

"Grau, theurer Freund, ist alle Theorie.
Und grun des Lebens goldner Baum."

The only man he really loved and had use for was the man who could
bring him facts. To see facts, not to argue or _raisonniren_, was what
life meant for him; and I think he often positively loathed the
ratiocinating type of mind. "Mr. Blank, you are _totally_ uneducated!"
I heard him once say to a student who propounded to him some glittering
theoretic generality. And on a similar occasion he gave an admonition
that must have sunk deep into the heart of him to whom it was
addressed. "Mr. X, some people perhaps now consider you a bright young
man; but when you are fifty years old, if they ever speak of you then,
what they will say will be this: 'That X,--oh, yes, I know him; he used
to be a very bright young man!'" Happy is the conceited youth who at
the proper moment receives such salutary cold water therapeutics as
this from one who, in other respects, is a kind friend. We cannot all
escape from being abstractionists. I myself, for instance, have never
been able to escape; but the hours I spent with Agassiz so taught me
the difference between all possible abstractionists and all livers in
the light of the world's concrete fulness, that I have never been able
to forget it. Both kinds of mind have their place in the infinite
design, but there can be no question as to w