ON THE FOOD OF PLANTS. 101 



food fit for the reception and nourishment of 

 plants. 



Salts are various in their nature and general 

 effects, when placed in contact with other sub- 

 stances. 



I have made many experiments with sea-salt, 

 nitre, soda, barilla, alum, &c., and have never 

 found them operate as a proportional addition of 

 food may be expected to do. 



The opinions of Drs. Smith and Pearson on this 

 subject appear more rational. They say, that salts, 

 as they operate in promoting vegetation, are ana- 

 logous to mustard, cinnamon, ginger, &c., which 

 are not of themselves at all, or necessarily nu- 

 tritious, but contribute to render other things 

 nutritious, by exciting the action of the stomach 

 and other organs of digestion and assimilation. 

 Salts being considered to operate in this manner, 

 in promoting vegetation, we are naturally led to 

 their proper application, that is, in small quan- 

 tities, or in a state of weak solution. 



Notwithstanding all that has been said to es- 

 tablish the opinion, that sea-salt is a valuable 

 manure, I am convinced it never can, as an 

 article of food, contribute to the increase of any 

 vegetable ; but as a chemical agent, by destroying, 

 and facilitating the decomposition, of animals and 



II 3 



