66 On a Leather-like Substance composed o/' Infusoria. 



of this natural production^ as you will observe, resembles soft 

 dressed glove-leather, or fine paper, is shining, smooth to the 

 touch, and of the toughness of common printing-paper*. On 

 the inner side, which was in contact with the water, it has a 

 lively green colour, and one can still distinguish green leaves, 

 which have formed the leather-like pellicle. I dare say a bo- 

 tanist could still determine the species to which they belong. 



I have made the following experiments on the leather-like 

 substance, having separated it from the green inner coat. 



It catches fire very easily, burns with a wax-yellow flame, 

 leaving a pale-red rough light ash. When heated in a small 

 retort dense white fumes are evolved, an odour of burnt paper 

 is perceived, and simultaneously drops of a yellow empyreu- 

 matic oil are deposited on the neck of the retort. Somewhat 

 later, water, having a strong acid action, is given off, which 

 evaporates without leaving any residue. A light charcoal re- 

 mains in the bottom of the retort. 



Water, alcohol, aether, nitric acid and aqua regia have no 

 action on it, nothing being dissolved, nor does its texture alter 

 when heated with these re-agents. A solution of hydrate of 

 potassa dissolves it to a brown slimy fluid ; caustic ammonia 

 has at first only a slight action, but after some days it swells 

 out, becomes like wet printing paper, and is partially altered. 



If the substance is gradually heated with hydrate of potassa, 

 and the gas then given off conducted into a solution of nitrate 

 of mercury, there is wo black precipitate, neither are white 

 fumes observable when the gas is brought into contact with a 

 glass rod dipped in acetic acid : consequently no ammonia is 

 formed when the substance is burnt, and, therefore, it can con- 

 tain little or no nitrogen. The ash of itself, or when moistened 

 with sulphuric acid, does not colour the oxidizing flame of the 

 blowpipe. In borax it is dissolved, giving a gloss which while 

 warm is of a deep yellow, when cold of a pale yellow colour. 

 With the double salt phosphate of soda and phosphate of am- 

 monia it gives a pale yellow glass, leaving a thin scale of si- 

 lica. Fused with soda and saltpetre on a platinum plate the 

 ash gives a deep green mass. It has no alkaline action, does 

 not effervesce with acids, nor does it contain any salt soluble 

 in hot or cold water. 



Thus the ash of the substance in question is composed es- 

 sentially of silica, oxide of manganese and oxide of iron. The 

 substance itself appears to be an aggregation of leaves, from 

 which the green colouring matter, the extractive matter, and 

 also the organic matters have by some organic process entirely 

 disappeared. 



* Unsized paper. — Edit. 



