STABCH-PBODUCING PLANTS. 331 



water added, which process was repeated until every foreign sub- 

 stance appeared to be removed ; the produce of these several ope- 

 rations 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. Dims. Centes. prop. 



Root of the sweet cassava (Janipha Loeflingif) . 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 (Husa 



paradisiacal) . . , . . . . 11 1 13.82 



Root of the Guinea yam (Dioscorea bulbifera) . 8 6 30.46 



Root of the sweet potato (Batatas edulis) ..86 10.46 



Root of the arrowroot (Maranta arundinaced] .56 6.71 

 The full-grown but unripe fruit of the banana 



(Musa sapientuni) 00 0.0 



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 experi- 

 ments, or, if not, may we not suspect some inaccuracy in the pro- 

 portion 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 appli- 

 cable to human sustenance, especially the roots which yield the 

 farinaceous starch of the South Sea islanders, to the achira of 

 Choco, &c. 



I shall extract largely from a very valuable report drawn up by 

 Dr. John Shier, agricultural chemist, of Demerara, and submitted 

 to the G-overnor of that colony in 1847, on the starch-producing 

 plants, which is deserving of more widely extended publicity than 

 the merely local circulation it has received. The remarks and 

 results of experiments are worthy of deep consideration ; and 

 although they were meant to apply specially to British Guiana, they 

 are equally pertinent to the West India colonies generally, our 

 African and Australian settlements, and many other of our foreign 

 possessions. 



For many reasons it is desirable that the number of the staples 

 of cultivation and export of our colonies should be increased. It 

 is the general experience of British agriculturists, that the mixed 

 system of agriculture is more profitable to the farmer and safer 

 for the land, than the continued cultivation of any single crop, or 



