Experiments and Olservations on Lac. 1 9 



An account of the latter substance has been published 

 hy Dr. Bostock, of Liverpool, in Nicholson's Journal, 

 with comparative Experiments and Observations on Bees- 

 Wax, Spermaceti, Adipocire, and the crystalline Matter 

 of biliary Calculi*. 



The properties of the myrtle wax, as described in Dr. 

 Bostock's valuable paper, so perfectly coincide with those 

 which I have observed in the wax of lac, that I cannot but 

 consider them as almost the same substance; indeed I 

 think they may be regarded as absolutely identical, if some 

 allowance be made for the slight modifications which have 

 been produced by the different mode of their formation. 



From the preceding experiments and analyses we find, 

 that the varieties of lac consist of the four substances which 

 have been described ; namely, extractive colouring matter, 

 resin, gluten, and a peculiar kind of wax. Resin is the 

 predominant substance ; but this, as well as the other in- 

 gredients, is liable, in a certain degree, to vfwiation in re- 

 spect to quantity. 



According to the analyses which have been described, one 

 hundred parts of each variety of lac yielded as follows. 



98.20 



NiclioUon's Journal for March 1803, p. 129. 



B2 The 



