The Commercial Products of the Vegetable Kingdom / Considered in Their Various Uses to Man and in Their Relation to the Arts and Manufactures; Forming a Practical Treatise & Handbook of Reference for the Colonist, Manufacturer, Merchant, and Consumer, on the Cultivation, Preparation for Shipment, and Commercial Value, &c. of the Various Substances Obtained From Trees and Plants, Entering into the Husbandry of Tropical and Sub-tropical Regions, &c.

by P. L. Simmonds

9. Is the process attended with any particular difficulties that ought to deter the East and West India planters from engaging in it?

In the following observations (continues Dr. Shier) I shall be able to reply to several of these questions, especially those capable of being settled in the laboratory. On other points, particularly those relating to the returns per acre, I am at present but imperfectly informed, in consequence of the limited extent to which these plants have hitherto been cultivated in this colony (Demerara), and from the total absence of authentic data regarding the amount of yield.

Characters of starch produced from different plants.—Starches from different plants are best distinguished from one another by examination under a good miscroscope. The grains or globules may be examined either as transparent or opaque objects; and although in the same species there are considerable differences in size and form, the different kinds are, on the whole, quite distinguishable. One of the best ways of examining the form of the globules, under the microscope, is to lay them on a plate of glass and cover them with a drop of aqueous solution of iodine, which renders them gradually blue and opaque. When the difference in size and form between the globules of different species is considerable, as between the Tous les mois starch and cassava starch, or even between the arrowroot starch and cassava starch frequently used to adulterate it, it is not difficult, with a little practice, to detect the fraud.

TABLE ILLUSTRATIVE OF THE SIZE AND FORM OF THE STARCH GLOBULES OF VARIOUS PLANTS.

1. Tous-les-mois (Canna coccinea).—Grown in Grenada, 1-300 to 1-2,000 of an inch; general size, 1-500; form of the globules, large, elliptical and ovate, and remarkably transparent.

2. Ditto ditto (species unknown).—From a plant grown in the garden of the Hon. J. Croal, Georgetown, but gathered before the root was fully ripe; globules spherical, shortly ovate and elliptical; size, from 1-600 to 1-1,600; general size, 1-800.

3. Buck Yam (Dioscorea triphylla).—Grown on the banks of the Demerara River. Form of globules, elliptical, often truncated at one end, so as to be mullar-shaped, some pear-shaped; length, twice the width; size, 1-600 to 1-2,000; general size, 1-800.

4. Common Yam (D. sativa).—Grown on No. 1 Canal, Demerara River. Elliptical, some long elliptical; size, 1-700 to 1-2,000; general size, 1-1,000.

5. Guinea Yam (D. aculeata).—Grown in the same locality. Larger globules, elliptical; smaller ditto, spherical, often truncated; some shortly ovate, with the appearance of being flattened; general size and range, same as No. 4.

6. Barbados Yam, grown on banks of Demerara river. Globules, pear-shaped and mullar-shaped; range, 1-700 to 1-1,600; general size, 1-1,000.