26 



In a note to this last paragraph we are told that — 

 Langlois has lately observed, during the dry summer of 1842, that 

 the leaves of the linden-tree became covered with a thick and sweet liquid 

 in such quantities that for several hours of the day it ran off the leaves 

 like drops of rain. Many kilograms might have been collected from a 

 moderate-sized linden-tree. 



And further on, at page 141, he says, — 



In a hot summer, when the deficiency of moisture prevents the ab- 

 sorption of alkalies, we observe the leaves of the lime-tree, and of other 

 trees, covered with a thick liquid containing a large quantity of sugar ; 

 the carbon of the sugar must without doubt be obtained from the 

 carbonic acid of the air. The generation of the sugar takes place in the 

 leaves, and all the constituents of the leaves, including the alkalies and 

 alkahne earths, must participate in effecting its formation. Sugar does 

 not exude from the leaves in moist seasons, and this leads us to con- 

 jecture that the carbon which appeared as sugar in the former case would 

 have been applied in the formation of other constituents of the tree in 

 the event of its having had a free and unimpeded circulation. 



These quotations will probably be considered sufficient to justify 

 the assertion that the gathering of the honey from plants can in no 

 possible way tend to exhaust the soil^ or affect its fertility. There 

 is no difference of opinion amongst scientific men as to the sources 

 from which the saccharine matter of plants is derived. Since 

 Liebig first put forward his views on that subject^ as well as with 

 regard to the sources from which the plants derive their nitrogen, 

 the principles of agricultural chemistry have been studied by the 

 most eminent chemists, some of whom combated the views of Liebig 

 on this latter point (the source of nitrogen and its compounds), and 

 Liebig himself seems to have modified his views on that point; but 

 there has been no difference of opinion about the saccharine matter, 

 as to which Liebig's doctrine will be found given unaltered in the 

 latest colonial work on the subject, Maclvor's " Chemistry of Agri- 

 culture," published at Melbourne a fe,w years ago. 



Superfluous Nectar evaporated ip not taken by Insects. 

 That the nutritive quality of the plants in any growing crop is 

 not diminished by the abstraction of honey from their blossoms 

 would appear to be evident from the fact already referred to, that 

 those plants have actually thrown off the honey from the svperfluity 

 of their saccharine juices, as a matter which they could no longer 

 assimilate. There would appear, on the other hand, to be good 

 reason to believe that the plants themselves become daily more nutri- 

 tive during the period of their giving off honey — that" is, from the 

 time of flowering to that of ripening their seeds. Tliis is a point 

 upon which, I believe, all agricultural chemists are not quite agreed, 

 but the testimony of Sir H. Davy is very strong in favour of it. In 



