IOO ABSORPTION OF LEAVES. 



That wax is also an exudation from the leaves 

 of plants, appears from the experiments re- 

 corded by Dr. Thomson in his Chemistry, 

 v. 4, 298, and it has been long ago asserted 

 that wax may easily be gathered from the 

 leaves of Rosemary. On this subject I have 

 not made any experiments to satisfy my- 

 self. 



With respect to the absorbing power of 

 leaves, the best observations that have beeix 

 made are those of Bonnet, recorded in the 

 beginning of his Recherches sur l' Usage des 

 Feuilles. His aim was., by laying leaves of 

 various plants upon the top of a jar of water, 

 some with their upper, and others of the 

 same species with their under, surfaces ap- 

 plied to the water, to discover in which situa- 

 tion the leaves of each plant continued longest 

 in health and vigour, and also how far dif- 

 ferent species differed from each other in this 

 respect. The results were in many instances 

 highly curious. 



Of fourteen herbaceous plants tried by this 



prove honey-dew to be the dung of dphides. I only 

 contend that there are more than one kind of honey- 

 dew. 



