192 Plants. 



Some botanists have conceived that 

 plants, as well as animals, have a regular 

 circulation of their fluids. Others thinfc 

 this very improbable. On both sides, 

 recourse has been had to experiments, 

 and from these conclusions perfectly op- 

 posite have been deduced ; so that no 

 certain conclusion can be drawn on this 

 head. 



Light has great effect on vegetation. 

 Plants that grow in the shade, or in dark- 

 ness, are pale, and without colour ; and 

 the more they are exposed to the light, 

 the more colour they acquire. 



Vegetables are not only indebted to 

 light for their colour ; their taste and 

 odour are derived from the same source. 

 Hence it happens that hot climates are 

 the native countries of perfumes, odori- 

 ferous fruits, and aromatic resins. 



The action of light on the organs of 

 plants, causes them to pour out streams 

 of pure air from the surfaces of their 

 leaves, while exposed to the sun ; where- 

 as, on the contrary, when in the shade, 

 and at night, they emit air of a noxious, 

 quality. 



The various secretions of vegetables^ 



