The Natural System of Botany. 179 



carefully eradicated as soon as its flowers are sufficiently ex- 

 panded for their true character to be ascertained. By atten- 

 tion to such rules, Turnip-rooted and Long-rooted, White, and 

 Scarlet, and Purple Radishes, and all the different races of 

 Turnips, have been preserved for years ; whereas, if great 

 precautions had not been constantly taken to maintain them in 

 their purity, they would long since have become thrown to- 

 gether, and reconverted into the wild form from whence thev 

 sprang. 



The varieties of Cabbage and Cauliflower, are very nume- 

 rous, and many are too well known to require mention. One 

 or two are, however, very remarkable for their. size. The 

 palm-Kale, which is much cultivated in the islands of the 

 British Channel, grows to the height often or twelve feet, and 

 another kind, the Tree-Kale, used in France as fodder for cat- 

 tle, sometimes attains the height of sixteen feet. A species of 

 Brassica, very like the Turnip, furnishes Rape-seed, from 

 which is pressed a much used oil, while the refuse is a nutri- 

 tious food for cattle, under the name of oil-cake. 



Among other Cruciferae in common use, may be named the 

 different kinds of Mustard, Cress and Horse-radish, and the 

 Juris, from which the blue dye called Woad is obtained. 



The plants of this order are more abundant in Europe than 

 in any other quarter of the globe, only ninety out of the nine 

 hundred species being peculiar to America. Their general 

 character, as already stated, is to possess, in some degree, ac- 

 rid and stimulating properties, such as are observed in mustard 

 and horse-radish. None of the order are poisonous, and most 

 of the species are very useful remedies for that dreadful malady, 

 the scurvy, which, until late improvements in provisioning ves- 

 sels, was a terrible scourge to crews upon long voyages. In this 

 connexion ought to be mentioned a striking illustration of the 

 utility of a knowledge of the Natural System. During Lord 

 Anson's voyage round the world, near the beginning of the last 

 century, a very large proportion of his crew lost their lives, 

 or were rendered unfit for service, by the Scurvy; and 

 although new and unknown lands, teeming with luxurious 

 vegetation, were constantly being discovered, yet the dread 

 which the surgeon entertained of the men being poisoned, was 



