Milk of the Cow-Tree. 237 



A portion of it was put into a small retort, and left ex- 

 posed to a heat so regulated as never to exceed 212. A trans- 

 parent, colourless liquid gradually distilled over. This liquid 

 had an acid but at the same time a sweetish taste. It redden- 

 ed vegetable blues, and had the peculiar smell which characte- 

 rized the cow-tree milk. To determine the nature of the acid, 

 I put the liquid into a flask, with some pure carbonate of lime 

 in powder, and digested the mixture till the liquid had lost 

 the property of reddening vegetable blues. The portion of 

 calcareous-spar which remained undissolved had assumed a red- 

 dish-brown colour, and a slimy consistence. The liquid, which 

 was colourless, was filtered, evaporated to dryness, and the 

 saline residue exposed to a heat somewhat higher than 300, 

 to decompose any vegetable matter with which the calcareous 

 salt might be mixed. The brown residue was again digest- 

 ed in water, and the filtered liquid was a second time evapo- 

 rated to dryness. A small quantity of white calcareous salt was 

 obtained, on which a little sulphuric acid was poured, and heat 

 applied. A strong odour of acetic acid was exhaled, showing 

 that the small quantity of uncombined acid in the tree milk is 

 the acetic. 



When the cow-tree milk is mixed with caustic potash ley, or 

 with dilute nitric, muriatic, or sulphuric acids, and then thrown 

 on a filter, a dark brown coloured liquid passes through, and a 

 white substance, not unlike wax, remains on the filter. But I 

 could not succeed by this method in freeing the waxy matter 

 from all impurities. 



When the cow-tree milk is exposed to a low heat in an open 

 vessel, the moisture is gradually dissipated, and a solid, grey 

 waxy matter remains. When this matter is digested in water, 

 it becomes white and opaque, while the water assumes a yellow 

 colour, and, when concentrated, acquires the same dark reddish- 

 brown colour which characterizes the liquid which passes through 

 when the cow-tree milk is thrown on a filter. This liquid, how 



n h 2 



