prehension is felt on account of disease, a week's delay in
commencing on the crop will be found of great importance both to the
bulk and quality; for just previous to the decay of the tops, if
pleasant weather prevails and the ground is sufficiently moist, the
tubers increase in size with great rapidity.

"Late varieties usually constitute the great portion of the main crop,
and are those which require most care in taking up and storing. So long
as the plants continue green, the Potato should be allowed to remain in
the ground; as this is quite indicative that the tubers have not arrived
at full maturity."

In the preservation of potatoes, it is of the first importance that they
be excluded from light. If this is neglected, they become not only
injurious, but actually poisonous; and this is especially the fact when
they are allowed to become of a green color, which they readily will do
on exposure to the light. In a state of complete darkness they should
therefore be placed, the day they are taken out of the ground; and it
were even better that they were stored in rather a damp state, than that
they should be exposed for a day to the light with a view to dry them.
Drying has a bad effect on the skin of the Potato; for, if subjected to
this, the skin and part of the epidermis are made to part with their
natural juices, which ever afterwards renders them incapable of
absorbing moisture, even if presented to them. Fermentation is also an
important evil to be guarded against, as it changes the whole substance
of the Potato, and, so far as seed potatoes are concerned, destroys
their vegetative principle. As security against this, they should be
stored either in barrels or boxes, or in long, narrow ridges, with
partitions of earth between. Potatoes once dried should never be again
moistened until just before using.

"Keeping potatoes has the effect of diminishing the quantity of starch
contained in them. According to Mr. Johnson, those which in October
yielded readily seventeen per cent of starch, gave, in the following
April, only fourteen and a half per cent. The effect of frost is also to
lessen the quantity of starch. It acts chiefly upon the vascular and
albuminous part; but it also converts a portion of the starch into
sugar: hence the sweetish taste of frosted potatoes."--_M'Int._

_Varieties._--Messrs. Peter Lawson and Sons describe one hundred and
seventy-five varieties: and other foreign authors enumerate upward