BOOK II, 



THE PHYSIOLOGY OF PLANTS. 

 CHAPTEE I. 



ABSORPTION. 



It is to the root and leaf that nature has intrusted the 

 great source of nourishment — absorption. 



The leaves imbibe moisture by the whole of their sur- 

 face, by every pore, whilst it is only by their fine hair-like 

 fibres that roots take up water from the soil. And still 

 further, in the root absorption is absolutely restricted as 

 to extent; it does not take place through the whole of 

 the capillary filaments, but only by the microscopic 

 spongiole which terminates each of them, and acts the 

 part of a sucker. Hence Linnseus compared the roots to 

 the chyliferous vessels of animals. 



The great roots of vegetables, to which the vulgar 

 naturally attribute the principal function of life, have 

 really nothing to do with it. A very simple experiment 

 proves this. If we place the body of the root of a plant 

 in dry sand, whilst the fine ends of the roots are in suitable 

 soil or in water, it continues to grow, displaying the 



