288 INTERNATIONAL EXHIBITION, 1862. 



18612. and ascribe to it no purgative properties, at least while it is 

 fresh. The manna is deposited upon the trees much more 

 copiously after misty weather than at any other period. The 



Oak Manna, sample of oak-manna in the Exhibition constitutes a moist but 

 solid mass of agglutinated tears, closely resembling some of the 

 common qualities of ash-manna. Its taste is simply saccharine, 

 and agreeable. 



Australian 2. Eucalyptus Manna. There are several specimens in the 



^M^nn^*" 1 Exhibition of this substance, which is found in the form of 

 small rounded opaque- white masses upon the leaves and younger 

 branches of Eucalyptus mminalis, La BiL The exudation, which 

 is said to result from the punctures of insects, takes place most 

 copiously in the early part of summer, at which time the manna 

 appears as a transparent liquid, resembling thin honey, and 

 gradually solidifies. This Australian manna has not hitherto 

 been collected for medicinal purposes. 

 Lerp 3. Australian Insect-Manna called Lerp. Having only 



[Australian]. recen tly obtained a specimen of this substance, which to me was 

 previously unknown, I am unable to offer much information 

 respecting it. According to the Victorian Exhibition Report, pub- 

 lished at Melbourne this year, we find the leaves of Eucalyptus 

 dumosd, Cunn., called by the colonists Malle Scrub, become coated 

 at certain seasons of the year with an opaque white saccharine 

 substance in such profusion, that the shrubby vegetation has the 

 appearance of being iced. This substance, which among the 

 aborigines of the northern districts of the colony obtains the 

 name lerp, is the secretion of an insect of the Psylla family, and 

 consists (judging from the specimen in my possession) of a 

 series of depressed hemispherical cells, each from a tenth to a 

 sixth of an inch in diameter, placed contiguous to each other, 

 and adhering together so as to form irregular flakes, sometimes 

 an inch or more across. These cells are composed of a semi- 

 transparent, colourless, or yellowish substance, which is some- 

 what smooth in their interior, but which on their external 

 surface forms transparent woolly filaments, so closely interwoven 

 that the outer surface of a flake shows no evidence of the cellu- 

 lar structure beneath. Each cell is the habitat of an insect, 



