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 arrowroot (Maranta
arundinacea) 5 6 6.71
The full-grown but unripe fruit of the banana
(Musa sapientum) 0 0 0.00

This table exhibits, no doubt, very unexpected results, since it places the sweet cassava at the very top, and the banana at the lowest place in the list, while the bitter cassava, which seems to be little more than a variety of the sweet, notwithstanding its being the staple material of West Indian bread, occupies two places lower down, and is followed by the plantain.  The sweet potato and the yam, both of which are considered to be less nutritious than the arrowroot, rank above it in the centesimal proportion of their amylaceous produce.  Upon what, then, do the nutritive properties of these various substances depend?  Is it upon a gluten which was overlooked by Mr. Harris, in his experiments, or, if not, may we not suspect some inaccuracy in the proportion of starch assigned by him to each?  It is to be wished that similar experiments were repeated with care in different quarters, and the list extended to other tropical products applicable to human sustenance, especially the roots which yield the farinaceous starch of the South Sea islanders, to the achira of Choco, &c.