In October, 1849, Agassiz, in reply to a request from Thoreau that he
would lecture in Bangor, sent this characteristic letter:--
"I remember with much pleasure the time when you used to send me
specimens from your vicinity, and also our short interview in the
Marlborough Chapel.[35] I am under too many obligations of your
kindness to forget it. I am very sorry that I missed your visit in
Boston; but for eighteen months I have now been settled in Cambridge.
It would give me great pleasure to engage for the lectures you ask
from me for the Bangor Lyceum; but I find it has been last winter such
a heavy tax upon my health, that I wish for the present to make no
engagements; as I have some hope of making my living this year by
other efforts,--and beyond the necessity of my wants, both domestic
and scientific, I am determined not to exert myself; as all the time I
can thus secure to myself must be exclusively devoted to science. My
only business is my intercourse with nature; and could I do without
draughtsmen, lithographers, etc., I would live still more retired.
This will satisfy you that whenever you come this way I shall be
delighted to see you,--since I have also heard something of your mode
of living."
* * * * *
Agassiz had reason indeed to remember the collections made by Thoreau,
since (from the letters of Mr. Cabot) they aided him much in his
comparison of the American with the European fishes. When the first
firkin of Concord fish arrived in Boston, where Agassiz was then
working, "he was highly delighted, and began immediately to spread
them out and arrange them for his draughtsman. Some of the species he
had seen before, but never in so fresh condition; others, as the
breams and the pout, he had seen only in spirits, and the little
tortoise he knew only from the books. I am sure you would have felt
fully repaid for your trouble," adds Mr. Cabot, "if you could have
seen the eager satisfaction with which he surveyed each fin and
scale." Agassiz himself wrote the same day: "I have been highly
pleased to find that the small mud turtle was really the _Sternothærus
odoratus_, as I suspected,--a very rare species, quite distinct from
the snapping turtle. The suckers were all of one and the same species
(_Catastomus tuberculatus_); the female has the tubercles. As I am
very anxious to send some snapping turtles home with my first boxes, I
would thank Mr. T. very much if he could have some taken for me."
Mr. Cabot goes on: "Of the perch Agassiz remarked that it was almost
identical with that of Europe, but distinguishable, on close
examination, by the tubercles on the sub-operculum.... More of the
painted tortoises would be acceptable. The snapping turtles are very
interesting to him as forming a transition from the turtles proper to
the alligator and crocodile.... We have received three boxes from you
since the first." (May 27.) "Agassiz was much surprised and pleased at
the extent of the collections you sent during his absence in New York.
Among the fishes there is one, and probably two, new species. The
fresh-water smelt he does not know. He is very anxious to see the
pickerel with the long snout, which he suspects may be the _Esox
estor_, or Maskalongé; he has seen this at Albany.... As to the minks,
etc., I know they would all be very acceptable to him. When I asked
him about these, and more specimens of what you have sent, he said, 'I
dare not make any request, for I do not know how much trouble I may be
giving to Mr. Thoreau; but my method of examination requires many more
specimens than most naturalists would care for.'" (June 1.) "Agassiz
is delighted to find one, and he thinks two, more new species; one is
a Pomotis,--the bream without the red spot in the operculum, and with
a red belly and fins. The other is the shallower and lighter colored
shiner. The four dace you sent last are _Leuciscus argenteus_. They
are different from that you sent before under this name, but which was
a new species. Of the four kinds of minnow, two are new. There is a
black sucker (_Catastomus nigricans_), but there has been no specimen
among those you have sent, and A. has never seen a specimen. He seemed
to know your mouse, and called it the white-bellied mouse. It was the
first specimen he had seen. I am in hopes to bring or send him to
Concord, to look after new _Leucisci_, etc." Agassiz did afterwards
come, more than once, and examined turtles with Thoreau.
Soon after this scientific correspondence, Thoreau left his retreat by
Walden to take the place of Emerson in his household, while his friend
went to visit Carlyle and give lectures in England. The letters that
follow are among the longest Thoreau ever composed, and will give a
new conception of the writer to those who may have figured him as a
cold, stoical, or selfish person, withdrawn from society and its
duties. The first describes the setting out of Emerson for Europe.