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The great importance in the animal economy in many species 

 of plants, as food for man and animals, as well a^ the great beauty 

 of others, has long since made the organization of this class of 

 beings, the laws that govern their growth, the mode by which 

 they receive and assimilate their nourishment, an attractive object 

 of profound investigation, and the various discoveries made, and 

 conclusions aimed at with respect to these subjects, have been 

 embodied as a science under the name of vegetable physiology. 

 From the very nature of this science, occnpied with the secret 

 and hidden processes of nature, and these processes operated 

 upon and controlled by that of all other most mysterious of 

 principles, the principle of vitality, its deductions must be to a 

 certain extent vague and uncertain. In order to arrive at more 

 satisfactory results, within a short period the principles of another 

 science, itself of comparatively recent origm, chemistry, have 

 been applied to the investigation of the various phenomena of 

 vegetable life, thus giving rise to a new branch of vegetable pliys- 

 iology, now known as agricultural chemistry. 



Agricultural chemistry occupies itself with the investigation of 

 the constituent elements, of organizea bodies of plants and animals 

 employed in husbandry, and as in the organization of each, chem- 

 ical action is constantly going on, action by which the nourishment 

 received, is converted into the substance or body of the plant or 

 animal itself, it seeks to ascertain the condition under which this 

 action occurs — the mode of its operation, the circumstances 

 attending it, and the best means of promoting it. 



Soils are known to consist of certain mineral and other 

 elementary substances, and the ash of plants to , ontain all those 

 inorganic elements, that are found in fertile soils — to ascertain 

 these various constituents — the quantities and proportions of 

 each, in both soils and plants, is an object of analytical chemistry. 

 So too, a soil may be so constituted, that in consequence of being 

 deficient in some one element, it is unproductive, and the expense 

 and labor bestowed on its cultivation, is in a great measure 

 thrown away ; here chemical analysis detects th*. deficiency, and 



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