PREFACE. VU 



precede any study of the particular chemistry of 

 plants or animals. It is also very desirable that 

 something should be known of the structure, and 

 processes of life in plants and animals ; such 

 knowledge is quite essential for clear ideas on 

 agricultural science. The teacher or student thus 

 furnished will be the one best able to make use of 

 the special information which it is the object of the 

 following pages to convey. 



It may perhaps be of service to mention a few 

 books which will be found useful by the student. 

 Among works on plant physiology we may name 

 the Text-Books of Botany by Thom6, and by Prantl 

 (Vine's translation), and the still more elementary 

 work by MclN'ab. ^'How Crops Grow" is an 

 excellent work, but is, we fear, out of print. 



In animal physiology Huxley's Elementary 

 Lessons may be particularly recommended. 



^'How Crops Feed" is an excellent work, chiefly 

 devoted to the chemistry of soil; it is now 

 somewhat old. 



There are also two capital little German works 

 by E. Wolff, embracing the whole subject of 



