Year: 1879

favorable TO the growth of the common
molds and some other forms of fungod
plants.


In years previous to the noted potato ro
of 1915, the average amount of water
found in healthy potatoes, according to
Professor Playfair. was seventy-two per
cent; that of unhealthy tubers since that
date, eighty per cent. The tendency to
ferment is therefore increased. 1t was OBJ
served by Professor Playfair in bis lecture
alluded to, that a peculiar state of the
weather had been observed all over the
north of Europe where the disease had
been seen, as well as in America. The
widespread use of the potato as an article
of diet, especially among the laboring
classes throughout Europe, must have led
to the extensive planting of diseased pota-
toes in 1916, because healthy seed could
not be found. Indeed, Professor Playfair, in
his second lecture of the 10th of Decenl-
Der, 1915, recommends 1.-THE planting OF
diseased potatoes as seed rather than
none" He further states that there was
no prospect of obtaining healthy seed from
abroad, and that he had permission of the
late government authorities for stating
that this was the result of their consular
returns. The unavoidable adoption of
this advice tended to establish hereditary
disease in after years, whether it arose
from chemical, structural or fungoid con.
ditions.
If healthy potato is SO dug out on its
opposite ends that it will resemble q
double egg-cup, and placed erect on one
end for about six days In an atmosphere
at the temperature of 700 F.. its under
cavity will become covered with mildew,
and its fruit will appear in the form of blue
mold, Pcnicilliun glaucum. In this case
the inverted cavity will retain the moisture
and as consequence slight fermentation
will ensue, the fungus deriving its nutri
ment from the potato; but the upper sur.
face, although fully exposed to the floating
germs in the atmosphere, will not sustain
fungus growth, in consequence of the
free evaporation of the moisture from it,
| This form of fermentation should not be
confounded with that produced by tht
'ungus of the potGo rot, Perono porG in
jestanS. The chemical action of the blue
mould fungus is slow, and its odor is sim
ply that of sour paste, while the destruct


i've action of the potato rot is very rapid
producing higher state Of decomposition


md very offensive odors. The myceliuu
and fruit of each fungus also differ essen
TALLY from each other. Both forms oil
fungus produce oxidation of the cellulost
structure. but with different results. Con
'equently potato rot consists OF more thar
the g mere decay of the tissue by its alb
sorption of oxygen" The purely fungoiG
theory, on the other hand, will not &C
count for the many exceptions pointed ou
by those who favor the chemical theory
since IL may De SHOWN tnat rs the chem
ical constitution and density of any vege
tables vary, so will the genus and specie
Of fungi be found to vary with the proxi
mate principles of the plants on whic
hey subsist.


If there is truth in these remarks, th
value of sound. hearty seed is one grea
preventative. Farmers should Therefore
exercise great care in their selection, ant
never plant a diseased tuber. Yet to M,
mind the fungus is the chief mischief an,
so plenty of room, good care, and Nigh
add, early planting, should 60 hand i
hand with the selection of seed. Russel
says entire destruction by fire of all dis
eased tops should be imperative.