APPENDIX P. 



541 



axillary buds specialised for storage and propagation, are deficient in 

 lats, and contain little proteitls. More than four-filths of the organic 

 substance is in the form of starch. Hence potatoes are used with 

 meat and fats to make a well-balanced meal. The proteid is largely 

 in the form of cubical crystalloids, located ner.r to the corky rind, and 

 thus liable to be removed by peeling the potato (Fig. 79, p. iro). 



TABLE OF ANALYSES OF ROOTS AND SHOOTS. 



N.B. — Vegetables used in the fresh state have a very high water- 

 content. This must be taken fully ijito account in considering their 

 value as foods. 



The Beet (Beta vulgaris and B. viaritima, L. Chenopodiaceae) grows 

 wild on sandy shores in the Mediterranean region, extending northwards 

 to our own coasts. Its originally slender root became fleshy from the 

 effects of soil and cultivation, and Vilmorin has .shown that it is one of 

 the plants most easily improved by selection. It has been cultivated 

 since before the Christian era. The fleshy root, characterised b}' 

 repeated cycles of separate vascular strands, as seen in transverse 

 section, contains cane-sugar in its sappy parenchyma. The analysis 

 shows, for garden Beet, over 14 per cent. ; but in specially selected 

 and cultivated sugar-beets the percentage is very much higher. It 

 has long been grown as a garden vegetable for winter use ; but latterly 

 it has become the chief European source of Sugar. 



The Parsnip (Pastinaca sativa, L. Umbelliferae) ranks liigh as a 

 nutritious vegetable. The original type is native in Britain ; it has 

 been cultivated since Roman times. The root, distended by cultivation, 

 is apt to be fibrous on poor soils ; but when well grown it contains a 

 high percentage of digestible carbohydrates. 



The Onion (Allium cepa. L. Liliaceae) was used as a condiment by 

 the Egyptians, Greeks, and Romans. It appears to have originated 

 from a wild species of the Middle East. The distended leaf-bases 

 form a bulb containing a large deposit of sugar. But it is as a 



