ACADEMY OF NATUKAL SCIENCES. 5 



vitality, and, consequently, to the circulation of sap and other 

 liquids. 



Such information is of no small value to the science of agri- 

 culture, which essentially consists in a knowledge of the most 

 successful means of feeding the various plants cultivated for food, 

 or for materials to be used in the arts and manufactures. When 

 the elementary composition of plants is ascertained through the 

 aid of chemistry, this knowledge of their vital functions enables 

 the agriculturist to select the soil, exposure, and manures best 

 adapted for each variety to obtain a lucrative crop. 



But this is not the only manner in which natural history has 

 led to improved and rational modes of cultivation. The labors 

 of botanists have exploded many false notions which prevailed 

 among farmers, calculated to discourage efforts to protect their 

 crops from injurious influences. A power of self-transmutation 

 was once attributed to plants ; ignorant persons believed that some 

 species were capable' of metamorphosing themselves into others. 

 It was once asserted and believed that " barley frequently dege- 

 nerates into oats" and even now some credulous persons contend 

 that "wheat is sometimes transformed into bromus or cheat."* 



Even purely descriptive botany may be usefully applied to _ 

 agriculture. Certain plants, which are injurious to cattle, will 

 be eaten by them when pasture is deficient ; and some noxious 

 plants will be eaten when dry and mingled with hay, which ani- 

 mals reject in the green state. A knowledge of descriptive 

 botany would enable the farmer to remove these, as well as pro- 

 fitless weeds, and thus improve his grounds for the advantage of 

 his stock. The wild flora of a country or district affords a 

 valuable indication of the nature of the soil and its subsoil. 

 " Thus, the heath on elevations indicates a dry soil ; the fern, that 

 it is deep as well as dry. The deer-hair (Scirpus ccespitosus] grows 

 commonly over bogs, resting on clay. In the lower situations, 

 the broom (Spartium scoparium) tenants the deep light gravels. 

 The whin, the coarser gravels upon a clay subsoil. The rush 

 (Juncus conglomeratus) tells the intelligent farmer that good land 

 is rendered useless for want of drainage. The common sprit 

 ( Juncus articulatus), that the land is not fertile. Sweet gale 



* Memorials of John Bartram and Humphrey Marshall. By William 

 \ Darlington, M. D., LL. D., &c. Philad., 1849. 



