f4 On the Feciila of Green Plants. 



which fall to the bottom. Albumen at that temperature 

 does not experience the slightest change. 



2d. Place over a furnace two matrasses, one with juice 

 diluted in twenty parts of water, and the other with albu- 

 men. But the fecula, however much diluted it may be, 

 will still be entirely separated bv the heat. It is here that 

 it clearly shows its insolubility. In regard to the water of 

 the albumen, in proportion as it is healed it becomes opa- 

 lised without ceasing to be transparent : it boils and is 

 concentrated, without depositing flakes or any thing that has 

 a resemblance to fccula. And if the evaporation be then 

 completed in an open vessel, it leaves nothinji but a varnish 

 of white of eo'g. Darcet had before informed us that al- 

 bumen diluted with a large quantity of water is no longer 

 separable by hcaf. Albumen is a soluble mucilage, fecula 

 is not ; and the temperature w hich coagulates the latter 

 makes no change in the state of the former. 



3d. Water of albumen may be kept several days without 

 alteration : on the other hand, the juice of plants is in a con- 

 tinual state of chance, which always disturbs its transpa- 

 rency. When a juice is filtered it becomes turbid, and it 

 does not cease to deposit white fecula. 



4th. Albumen makes the juice of violets incline to a 

 green colour, and reddens turnsole to blue. White fecula 

 when washed produces none of these changes : and how 

 should it ? The juice of cabbages, hemlock, and many 

 other plants, makes turnsole red. Albumen however has 

 not the property of communicating a green of itself : we 

 know that it is indebted for it to a mixture of alkali. 



5fh. Alcohol separates from the water of albumen light 

 transparent shining flakes, which on the filter retain the ap- 

 pearance of baked white of egg. The juice of plants with 

 alcohol gives only an opake whitish powder, which spee- 

 dily falls to the bottom of the vessel. 



6th. All acids, hydro-sulphurated water, and ammonia, 

 precipitate the fecula dissolved in juices; but these re-agents 

 make no change in water of albumen. 



Oxygenated nuiriatic acid precipitates and oxidates white 

 fecula. The same acid first oxidates and then precipitates 

 albumen. 



7lh. Crystallized carbonate of potash, magnesia, muriate 

 of soda, muriate of potash, nuiriate of ammonia, nitrate 

 'of potash. Sec. when thrown into filtered juice force the 

 fecula, which is naturally verv little soluble, to be precipi- 

 tated as it is dissolved. Water of albumen is not rendered 

 turbid by any of these salts. 



