372 OPINION OF MR. KNIGHT. 



must have been deceived in what he saw, and that the 

 honey dew is not an atmospheric phenomenon, but a posi- 

 tive secretion of certain trees and shrubs, and exuded by the 

 power of heat. 



" I have long adhered to the opinion," says Mr. Knight, 

 " that the honey dew dispersed on the leaves of the trees, 

 was only an exudation, although the form of the globules 

 scarcely bore any resemblance to each other, but were 

 rather an imitation of a species of rain. On examining 

 more minutely different trees on which the honey dew was 

 apparent, chance led me to the discovery of a holm-oak, on 

 which the honey dew had recently appeared, and in its primi- 

 tive form, which is that of a transfused humour. The leaves 

 were covered with several thousands of globules, or small 

 round and compact drops, which, however, seem to be either 

 touching or intermixing, similar to those which are seen on 

 the plants after a thick fog. The position of each globule 

 appeared to indicate, not only the point from which it ex- 

 uded, but also the number of the pores or the glands of the 

 leaf, in which this mellifluous juice had been prepared. I 

 assured myself that the honey dew possessed the real colour 

 of honey, which alone was sufficient to decide on its origin, 

 without at the same time removing the doubts which a con- 

 trary prejudice establishes. The honey dew of a neighbouring 

 bramble was not constituted the same ; the little globules 

 had no doubt commixed, or, being united to each other, 

 either by the humidity of the air, which had dilated them, 

 or by the heat, which had promoted their extension, they 

 formed large drops or broad layers, the dried matter of 

 which had become more viscous. It is under these latter 

 forms that the honey dew is commonly perceived, and our 

 surprise need not be great that exudation is not suspected 

 as the cause. 



"In the season when I remarked the honey dew in 

 globules on the evergreen oak, the tree bore two sorts of 



