LECT. II.] DEFINITION Otf A PLANT. 47 



Salts serve to stimulate plants, and, by exciting 

 the action of their irritable fibres, promote their 

 health and growth ; part of them are taken up 

 along with the soluble vegetable matter contained 

 in the soil, and disposed of in the economy of the 

 plant, either in the simple state in which they were 

 absorbed, or forming new compounds, generally 

 neutral salts ; and this is regulated by the peculiar 

 nature of the plant, independent of any properties 

 of the soil in which it grows. The same effect is 

 produced on animals, by the saline matters taken 

 into their stomachs along with their food. Some 

 of the lower animals, as earth-worms and other 

 speciesof the vermes, feed on vegetable and animal 

 matters which have undergone decomposition, and 

 returned to that state in which they are generally 

 found in soils. Vegetables, therefore, in common 

 with these animals, although certainly in a more 

 striking manner, have the power of recombining 

 and assimilating into organized bodies those ma- 

 terials which the loss of vitality had allowed to be 

 separated by the chemical affinities of their consti- 

 tuents, or to be decomposed, but are incapable of 

 transforming matter, which has never formed any 

 part of organized bodies, into their own living- 



we may ask the learned Professor, if phosphate of lime forms 

 a direct part of the food of animals, in order that bone be pro- 

 duced. 



