HONEY DEW THE EXUDATION OF PLANTS. 373 



leaves ; the old ones of a close texture, like those of the 

 holly, or of those trees which on the approach of winter do 

 not shed their leaves, and the new ones, which were yet 

 tender, and had shot forth only a short time. The honey 

 dew appeared constantly on the leaves of a year old ; the 

 leaves were however still covered with the tufts of the new 

 shoot, and consequently sheltered from all species of rime 

 or drizzling rain which might have fallen ; this is, in itself, 

 a convincing proof that the honey dew is not foreign to the 

 leaves of the trees which are moistened with it, and that it 

 never appears in any other place, as it is commonly sup- 

 posed ; as the new shoot of our evergreen oaks, which ought 

 to have been touched the first, as being the most exposed, 

 did not exhibit the smallest drop. 



" The same singularity struck me in regard to the honey 

 dew of the bramble ; although by the conformation of the 

 shrub, all its leaves are exposed nearly equally to the air, or 

 to the fall, which would take place vertically. The honey 

 dew only appears on the old leaves ; the new ones had not 

 more than the new shoot of the oak, of which mention has 

 just been made : the mellifluous juice not having had, with- 

 out doubt, a sufficient time to be formed in the tender part 

 of those vegetables, or to be extracted from the sap. It is 

 probably only the long exposition to the air, perhaps to its 

 intemperature, and especially to the sun, which ought to be 

 regarded as the true agent of the secretion. 



" To elucidate this subject further, the plants and shrubs 

 in the vicinity of the trees on which the honey dew appears, 

 but of a different species, and of a nature less suitable to 

 the formation of the juice, of which I am now speaking, do 

 not carry the least vestige of it. The honey never appears 

 on the rocks nor stones under the trees, on which it is 

 generally found, which is a fresh proof that this species of 

 liquid manna does not fall from the clouds like rain, as it 

 would diffuse itself indifferently on all kinds of bodies, and 

 r 3 



