a plant varies according to the period of
growth. The results of examination on the comparative yield of starch
in the potato, showed that while it abounded towards the latter part
of the season, it decreased when the tubers began to germinate in the
spring. It was found by Professor Balfour that 240 lbs. of potatoes
left in the ground, contained of starch--

lbs. Per cent.
In August 23 to 25 or 9.6 to 10.4
September 32 " 38 " 13.3 " 16
October 32 " 40 " 13.3 " 16.6
November 38 " 45 " 16 " 18.7
April 38 " 28 " 16 " 11.6
May 28 " 20 " 11.6 " 8.3

The quantity of starch remained the same during the dormant state of
winter, but decreased whenever the plant began to grow, and to require
a supply of nourishment.

Mr. Harris, of Jamaica, some years ago, made experiments upon the
nutritious qualities of the principal roots and vegetables of the West
Indies. These being well washed and scraped, were grated, in each case
into two gallons of clear rain-water, and the whole then filtered
through a clean linen strainer, after which it was left to settle;
when the amylaceous matter had wholly subsided the supernatant liquor
was carefully decanted, and fresh water added, which process was
repeated until every foreign substance appeared to be removed; the
produce of these several operations was then carefully collected and
dried with a temperature of about 110 deg. Fahrenheit, and, when dry,
weighed. In this manner the results given in the following table were
obtained:--

PRODUCE FROM FIVE POUNDS OF THE
Oz. Drms. Centes. prop.
Root of the sweet cassava (_Janipha
Loeflingii_) 14 1 17.27
Root of ocoes or taniers (_Caladium
esculentum_) 11 17 14.29
Root of the bitter cassava (_Janipha
manihot_), the Yucca amarga of the
Spaniards 11 2 13.90
Full grown but unripe fruit of the plantain
(_Musa paradisiaca_) 11 1 13.82
Root of the Guinea yam (_Dioscorea_
_bulbifera_) 8 6 10.46
Root of the sweet potato (_Batatas_
_edulis_) 8 6 10.46
Root of the arrowro