138 



produces in enormous quantities with very little attention. In the 

 ripe state the fruit is more or less mawkish, for the starch which 

 abounds in the unripe fruit becomes converted into mucilage and 

 sugar. It is highly nutritious, though less so than wheat and pota- 

 toes; yet the space occupied by their culture and the care required 

 are so much less that Humbolt has calculated the produce of 

 bananas, compared to that of wheat, as one hundred and thirty- 

 three to one, and to that of potatoes as forty-four to one. 



The Irish potato (solanum tuberosum) is cultivated for its under- 

 ground branches or tubers in all parts of the world. The introduc-' 

 tion of the potato in England is ascribed to certain colonists under 

 the auspices of Sir Walter Raleigh, who brought it from Virginia. 

 The plant is indigenuous in Chili and Peru. The potato contains 

 water amounting to three-fourths of its weight, and the remaining 

 fourth part being made up of starch, gum, sugar, albumen, vege- 

 table fibre and a very small proportion of fatty matter. 



Potatoes in cultivation are subject to a disease which is owing to 

 the presence of a fungus called batrytis infestaus, which first attacks 

 the leaves, causing discoloration, and thence spreads rapidly down 

 the stem to the tubers. The principal effect of the disease consists 

 in the increased quantity of water, the diminished quantity of starch 

 and the conversion of the albumine into casein. 



Potatoes contain a great quantity of starch, which is frequently 

 mixed with wheat flour in the manufacture of bread. This adulter- 

 ation can readily be detected by the microscope, especially on the 

 addition of a solution of potash, which causes the starch granules 

 of the potato to swell up, while no effect is produced on the starch 

 grains of wheat. The pulp of the potato, after the extraction of 

 the starch, becomes hard and horny when dried, and in this form it 

 is used in the manufacture of snuff boxes. 



Raw potatoes scraped are used as a popular cooling application 

 to burns and scalds. 



The tubers of this plant yield a coarse tasting brandy by distilla- 

 tion. The unripe berries of the potato plant are asserted to be 

 narcotic, and an extract prepared from the leaves has been employed 

 in coughs and spasmodic affections. 



The varieties of the potato are very numerous, some are early 

 and some late, and these differ in size, quality and color. It has 



