in the Year 1835, in reference to the Physiology of Plants, 157 



as that of the bloom of the fruit of this Cucurbitaceous plant. 

 The wax of this envelope melts, however, at a much lower 

 temperature, even below 80° Reaum., is little coloured, resem- 

 bles bees' wax, and has the same elementary composition. 



M. Mulder found in the husk or rind of coloured fruits, as 

 those of Pyrus Mains, Capsicum annuum, Sorbus aucuparia, 

 Cucurbita Lagenaria, invariably combined with the colouring 

 matter, a wax which was always found to be a pure cerin *. 

 By the experiment before mentioned, M. Du Menil obtained 

 from the bark of Finns sylvestris also 13 per M. of a whitish 

 wax, the nature of which was not more exactly determined f. 



M. Fr. Nees von Esenbeck and the author examined the 

 milk-sap of several fig trees J, in order to find whether the 

 Lacca in granis could originate from trees of this genus, as is 

 said, but must declare it to be erroneous ; and they were in- 

 duced to consider, as the only plant producing this remarkable 

 vegetable body, the Aleurites laccifera, which belongs to a 

 family the chemical constitution of which allows us to infer 

 the presence of similar resins to that which is contained in 

 seed-lac. 



At the same time they examined the milk- sap of Ficus 

 elastica from the stem as well as from the young branches; and 

 arrived at the result that the milk -sap of the young branches 

 consists of resin, gum, wax, together with some extractive 

 matter, a salt of lime, and a glutinous resin which was only 

 soluble in aether, not in alcohol, and which they believed to 

 be identical with the substance found by Macaire in Atractylis 

 gummifera, and named by him Viscin §. The milk-sap of the 

 old stem contained, on the contrary, caoutchouc instead of 

 viscin, and also the other constituent parts of the milk-sap of 

 the young branches, which is only observable when the milk- 

 sap is allowed to flow immediately into the aether. If it coagu- 

 lates in the air, traces only of resin, gum, and extractive matter 

 can be separated from the mass which has become caoutchouc 

 or elastic resin (Feder harz). The milk-saps of many other 

 species of this genus contained viscin, but in a few cases only 

 had it become caoutchouc in the old stems. M. Zeller || 

 found this viscin also in the berries of Sambucus Ebulus. 

 Without doubt the seed-lac [lacca in granis) belongs to the 

 coagulated milk-sapswhich have been drawn from the branches 

 of Aleurites laccifera ? by some peculiar lac Aphis. I ex- 



* Bydragen tot de naturkundige Wetenshappen, d. vii. No. 2. 



t Archivfur Pharmacie, vol. i. part 1. 



J Annalcn der Pharmacie, vol. xiv. part 1. 



*j Memoircs de la Soc. de Physique dc Geneve, torn. vi. "Sur la Viscin," &c. 



|| Wurtembergisches Correspondcnzcnblatt 1834. 



