372 



Jli'fliarist to .laiiics I. wliosr [lorti'ait was drawn with a shoot of 

 it ill his hand: and faNoiir did not tui'ii towards it nnlil wai's of 

 M-arcity caiiic. Scothind adopted it oidy in 17 lo. and it if(|uin'd 

 the <listn'ss of the Xa|»oh'onic wais to assist it to its phicc in 

 nofthcrn Kurojic. Italv. which now exports so nuich. was pai'ti- 

 rnlnrlv unwilling to have it at lirst. Vet for Kiiro])e in the six- 

 teenth (t'ntury in eoinpai'ison with the xciictahles then availahhj 

 it was unrivalled. 



The (n'eater Yiun is Dioseorea alata. a plant not at all allied 

 to the I'otato plant, althougii it fiiniishes a tuher which on cheiuical 

 analysis is seen to l)e extremely similar. Dr. Hooper in the .louiMial 

 of tile .\siatie Society of r.en-al. \. S. vii. I'.Ml. p. (id. nave the 

 lollowin::- comparison : — 



Yam I'otato 



Fat l.i)-^ (i.4(i 



Albuminoids lo.S?- lo.li 



C'arbohvdrates 7T.01 / o . -n 



Fibre ■ o.K! { '"^-'^ 



Ash 5.94 4.(J1 



Tlu' (ireater Yam is a nati\e of the Eastern Trojiics and has 

 been cultivated from the Indian Ocean to the Pacilic for a loni^- 

 time. Kverywhere between thesi' hounds, where the inhabitants had 

 attaineil some small degri'e (»f ci\ilisation over Ion*:' a<i'es it must 

 have held an imi)ortant place limited on the Fast and South by tlu' 

 Ocean and North by cold climates: fui-ther westward it was not 

 spi-cad becau.se bein>i- a wet tropical plant — moi'e intensely so than 

 the Sugar-eane, — it was unable to reach the continent of Europe, 

 even with the floors, on account of the dry countries which 

 separate India from the Mediterranean. It remained unknown to 

 Europeans until the Portuguese found it and provisioned their 

 ships with it. 



The same adventurous age which brought both the Potato and 

 the Yam to Europeau knowledge was the age which took the yam 

 to the New World, a com])etitor there with the tapioca ])lant. but 

 haiMlly with the potato. 



HoweMM' in India the yam anil the i)otato came into com- 

 petition in the nortliei'ii part of the countiw, and the yam lost 

 favoui- before its rival. iJnt while tlie potato is cultivable in the 

 r>eiigal i)lains. and on the plateaux further .south, so that Bombay 

 gets a suppiv Irom the Ghats behind it and the Madras Tresidency 

 has a s)nall >ui)ply from the Xilgiri Hills, it is not cultivable in 

 the i)lains south of the Tropic of Cancer; which means that over 

 a very large part of India the Greater yam has not been thrown into 

 com])etition by being grown and marketed alongside the potato, and 

 throughout the villages, of course where the rainfall is adequate, 

 it retains its old place as the chief of edible stachy tubers. Also 

 it still holds a place al)ove the potato elsewhere on account of the 

 baekwarduess or the peculiar local conservatism of the inhabitants. 



