250 



SWEET POTATO AETICHOKE CAEEOT 



This table, which assumes that all potatoes contain 5'8 per cent of 

 solid matter other than starch, can obviously have no claim to absolute 

 accuracy, but, for practical purposes, the method has proved very 

 useful. 



The Sweet Potato is the tuber of a convolvulus-like plant, Ipomcza 

 batatas, which grows in hot countries. It thrives best in light friable 

 soils, rich in organic matter, and, once established, will yield several 

 crops in successive years. It is propagated by cuttings. The tubers, 

 which sometimes attain a great size, are used in the same way as 

 ordinary potatoes, but are sweeter and less watery. The foliage is 

 eaten greedily by animals, but sometimes contains a cyanogenetic 

 glucoside which renders it poisonous, especially to pigs. From 0'014 

 to O019 per cent of hydrocyanic acid has been found in the green 

 material (i.e., from 1 grain to 1*33 grains per pound). 



The following analyses show the average composition of sweet 

 potatoes and their "vines " : 



Artichokes. The Jerusalem artichoke is the tuber of Helianthus 

 tuber -osus, and resembles the potato in composition except that it con- 

 tains inulin and laevulin instead of starch, and is usually more watery. 

 Its average composition is 



Water. Protein. Fat. Carbohydrates. Fibre. Ash. 

 79-6 1-5 0-2 16-9 0-7 1-1 



The globe artichoke (Cynara scolymus) is another kind of plant 

 which is grown for the sake of its unripe flower heads of thistle-like 

 character, a portion of which is edible after boiling. 



The Carrot, Daucus carota, and the Parsnip, Pastinaca sativa, 

 are sometimes grown as farm crops and furnish excellent, succulent 

 food for animals. The former is somewhat difficult to grow, on ac- 

 count of its slow growth in the early stages and the danger of the 

 crop being overgrown by weeds. Several varieties are known, but the 

 typical red or yellow carrot is rich in a colouring substance, carrotene, 



C 40 H 56' 



The Radish, Eaphanus sativa, of which there are several varieties, 

 is a cruciferous plant, grown rather as a market-garden crop than on 

 the farm. Average composition of the carrot, parsnip and radish : 



