250 AGRICULTURAL TEXT-BOOK. 



being celebrated for the quantity of good onions which they 

 produce and export. What are not required for home con 

 sumption are sent chiefly to the West Indies and South Amer 

 ica. The census takes no notice of this plant. From 1835 to 

 1845, 30,000 to 40,000 bushels and from 1850 to 1853 from 

 125,000 to 150,000 bushels a year were raised in the town 

 of Dauvers, Massachusetts, alone ; and though, to the farmer it 

 is rather an insignificant product, yet it employs many men and 

 women in its culture, and adds largely to the comfort of the 

 small cultivators of New England. Its moral effect is beneficial, 

 as it teaches the value of manure, of clean, neat cultivation, and 

 steady industry ; and it is said that onion-growing districts are 

 always remarkable for their prosperity, economy, and intelli 

 gence. 



552. Onions do not appear to have been accurately analysed. 

 They owe their peculiar odor and flavor, as well as their pun 

 gent and stimulating qualities, to an acrid volatile oil which 

 contains sulphur. When eaten, the oil becomes absorbed, 

 quickens the circulation and occasions thirst. According to 

 Fourcroy, Vauquelin and Le Grange, the following is the com 

 position : 



Acid volatile oil, 



Unorystaliizable sugar, 



Gum, 



Vegetable albumen, 



Starch, 



Woody fibre, 



Acetic and phosphoric acids, 



Phosphate and carbonate of lime, 



Sulphur, Water. 



The nourishing quality probably depends on some unknown 

 property of the oil, or an alkaline base, resembling creatine in 

 meat ; and may be classed with such sustaining substances as 

 chocolate, opium, &c., of the principle of which we are yet to 

 tally ignorant. The ashes contain alkaline and earthy salts. 

 This plant is used medicinally as a local irritant both internally 

 and externally; as an expectorant, diuretic, and anthelmintic. 

 Garlic is the most active of the family in its properties. 



553. The soil should be mellow, dry and rich : it need not, 



