
          Louisville, Ky. April 26th 1846

My dear Sir,

After a very long silence, which I began to
fear would never again be broken by you, I had the pleasure
not long since to receive your kind favour of the 18th March;
for which you will please accept my thanks. I am too well
informed of the multitudinous engagements which press upon you,
and the far more useful appropriation of your time, than in
writing to me, to have any improper feelings created in my bosom
by the long lapse of time since I have had the pleasure
of receiving a communication from you. Though myself an
“unprofitable servant” in this, and I fear also in many other respects,
yet I trust that I have the general zeal of our favorite 
Science so much at heart, as to be willing to give up
my own personal gratifications to its advancement. Little, however,
as I may have done in this field, yet I am sensible
that my labours in it are drawing to a close; and that I must
soon resign to stouter hearts and stronger limbs than mine, the
active cultivation of it. “To climb the mountains brow” has become
a task for which although “the spirit is willing yet the 
flesh is weak”. Although subject to [added: no] particular infirmity, yet I 
feel most sensibly, in my physical frame, that a man of 52, is

        