SUBJECT OF THE WORK 



hand, find new nutritive material only in inorganic substances. 

 Hence, one great end of' vegetable life is to generate matter 

 adapted for the nutrition of animals, out of inorganic substances, 

 which are not fitted for this purpose. Now, the purport of this 

 work is, to elucidate the chemical processes engaged in the 

 nutrition of vegetables, as well as the changes which they undergo 

 after death. 



The first part of it will be devoted to the examination of the 

 matters which supply the nutriment of plants, and of the changes 

 which these matters undergo in the living organism. The che- 

 mical compounds which afford to plants their principal constitu- 

 ents, viz., carbon, nitrogen, hydrogen, oxygen, and sulphur, will 

 here come under consideration, as well as the relations in which 

 the vital functions of vegetables stand to those of the animal 

 economy and to other phenomena of nature. 



The second part of the work will treat of the peculiar processes 

 usually described as fermentation, putrefaction, and decay. By 

 the action of these processes, the complete destruction of plants 

 and animals after death is effected. Hence the changes under- 

 gone by the elements of organic tissues in their conversion into 

 inorganic compounds, as well as the cause by which these changes 

 are determined, will become matter of inquiry. 



