INTRODUCTION". 11 



and to the atmosphere which constantly surrounds and 

 acts upon them. How the plant grows, the conditions 

 under which it flourishes or suffers detriment, the ma- 

 terials of which it is made, the mode of its construction 

 and organization, how it feeds upon the soil and air, 

 how it serves as food to animals, how the air, soil, 

 plant, and animal stand related to each other in a per- 

 petual round of the most beautiful and wonderful trans- 

 formations, these are some of the grand questions that 

 come before us ; and they are not less interesting to the 

 philosopher or man of culture, than important to the 

 farmer who depends upon their practical solution for his 

 comfort ; or to the statesman, who regards them in their 

 bearings upon the weightiest of political considerations. 



