The Stourbridge Observer, Cradley Heath, Halesowen & District Chronicle.
Stourbridge, West Midlands, England, 1875-05-22 00:00:00

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I " f-0 TO EDITOR, .OFI ITIVI..S,CIEWI7.fIIC;:;'" .
. ! AMERICAN. ' - • •
' .• •
,
Sir,—Having read a communication 'froth Mr.
',man Reed, of Boston, some months since, concern-
ink the cause of the potato rot, and referring the pro-
cuss to the action of microscopic parasites attacking
tile tubers, I devoted some spare hours to the verifica-
tiim of his view, which, with some modifications, I am
coMpelled to endorse. My investigations have been
cdnducted with an instrument magnifying 800
dlineters (640,000 times), assisted by a dissecting
microscope, giving 50 diameters, for the preparation
of sections and the isolation of specimens. My method
has been to procure specimens of the different
varieties, and, having carefully cleansed them,
to subject' them to gentle heat for 96 hours or
more, then to submit them to a careful exa-
mination. The ova of the insects seem to
occupy the interior layer of the cuticle of the
tubers, and pass rapidly into larva state under the
proper thermal condition. I have no doubt that they
commence that histolytic process which ends in the
destruction of the tuber ; but I doubt whether there is
any genetic connexion between the fungi developed in
the stalks in the -course of the degeneration and the
larva (larv) in which the degeneration primarily
starts. The fungi are very likely independent
structures resulting from the deposition of spores from
the atmosphere on vegetable tissue already in the
course of dissolution from other causes. Indeed, I may
say that from actual examination, I am assured that
such is the case, and that, as a general rule, vegetable
tissues develop microscopic fungi in the process of
breaking down, where similar spores deposited on
healthy tissue would remain undeveloped.
"I have made drawings of the larvw mentioned by
Mr. Reed in their various stages, and, what is more
important, have tested them with various re-agents.
Tested with weak solution of sulphuric acid, they
become very active for a few minutes then fall
into a torpid state, but finally recover. Substantially
the same effect is produced by alcohol. Ordinary
whale oil attacks them virulently in the laval state,
but not so virulently in the less-developed stages.
Kerosene oil is still more fatal to them in the
larval state, but unless a considerable quantity is
absorbed they gradually recover, and the younger
the larvm the less `rapidly they yield to the action of
kerosene. In some experiments prosecuted last summer
on what are generally known as apple-tree worms, the
same rule held good. Srwrna oil and kerosene were
both destructive to the fully-developed larvm, but very
inefficient when applied to the undeveloped ova. After
thoroughly testing the potato larvw in their various
stages with solutions of nitric, muriatic, sulphuric,
and oxalic acids, then with alcohol, sperm oil, and
kerosene, and with various alkalies, and finally with
iodine tincture, I was forced to the conclusion that
the remedy was not to be sought in this direction,
and tried a combination of one part of carbolic acid to
thirty parts of common whale oil, with unerringly
destructive results, both as respects the larvie and the
ova.
"If you will permit me on a subject of such import-
ance, through your universally read journal, I will
take the liberty of announcing that a bland solution of
carbolic acid in common whale oil, or kerosene, is the
scientific remedy for the rot. The best way to use it
would, I think, be to dip the potato, just before plant-
ing, in the solution, which is very inexpensive and very
easily obtained. I may add that my experiments con-
vince me that carbolic acid in this bland solution in no
way impairs the germinal activity of the tuber; but,
by way of certainty let me recommend your farmer
readers to first try the experiment on a few hills this
spring, and, if successful, to adopt it as a remedy for
the blight.
"I will, should you signify that it would be agree-
able t 9 you, be glad to give you full details of my in-
vestigations, accompanied with drawings of the insects
in the various stages, and descriptions of structure
and manner and development from the egg, of which I
have copious notes, according always to Mr. Reed the
full honour of first discovery.
"FRANCIS GERRY FAIRFIELD.