330 STARCH-PRODUCING PLANTS. 



aruudinacea, Allomyca and nobilis, and also from various species 

 of Canna called Tous les mois, and in the East Indies from species 

 of Curcuma, and from Maranta ramossissima in Silhet. 



The bread fruit (Artocarpus incisa), already alluded to, yields a 

 large quantity of starch ; as do the sweet potato (Convolvulus 

 Batatas, or Batatas edulis). The pith or farinaceous part of the 

 trunk of the Caryota urens, is almost equal to the finest sago. In 

 Assam the sago of this palm is much used. 



The two varieties of the Cassava afford a very superior fecula, 

 which is imported under the name of Brazilian arrowroot. 8,354 

 bags of tapioca and farina were imported from Maranham in 

 1834. Some excellent starch from Norfolk Island was shown at 

 the Great Exhibition. 



The Cycadaceous family yields much starchy matter, along with 

 mucilage. From the soft stems of Cycas revoluta and C. circi- 

 nalis, natives of China and the East Indies, a kind of sago is 

 made. These plants are propagated by suckers. Zamia pumila, 

 a native of the Cape of Good Hope, and other species of this 

 remarkable genus of plants, which is nearly related to both ferns 

 and palms, supply an amylaceous matter, which has been sold as 

 arrowroot. A similar product is obtained from Alstrcemeria 

 pallida, a perennial plant, with pink red flowers, growing in Chili. 

 Prom the nuts of the Cycas circinalis, the Singalese prepare 

 an inferior kind of starch, by pounding the fresh kernels. 

 These are cut in slices, and well dried in the sun before they are 

 fit for use, otherwise when eaten they are intoxicating, and occasion 

 vomiting and purging. 



The quantity of starch in 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 Ibs. of potatoes left in the ground, contained of 

 starch 



Ibs. 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 , 187 



April . . . . 38',, 38 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 sub- 

 sided, the supernatant liquor was carefully decanted, and fresh 



