1824.] Scientific Notices—Chemistry. 385 



state of ebullition, has a decidedly bitter taste. The volatility 

 of the sulphate of chinin had been previously taken notice of 

 by Callaud. — (Giornale di Fisica, &c. vi. 457.) 



3. Existence of Manna in the Leaves of Celery. 



Dr. A. Vogel finds the following substances in the leaves of 

 this plant (Apium graveole/is). 



1. A colourless volatile oil, in which resides the peculiar odour 

 of the plant. 



2. A thick fatty oil, partly combined with chlorophyle.* 



3. A distinct trace of sulphur. 



4. A tremulous jelly, or bassorine, which acquires a gelatinous 

 consistency, by the action of weak acids or of water. 



5. A brown extractive matter, soluble in alcohol, and precipi- 

 tated by solutions of tin and lead. 



6. Gum. 



7. Manna. 



8. A very considerable quantity of nitrate of potash. 



9. Muriate of potash. 



The manna may be extracted by boiling the filtered juice of 

 the leaves in order to precipitate the chlorophyle and vegetable 

 albumen, and evaporating the liquid thus purified, to the con- 

 sistency of honey : it separates on cooling in greyish white 

 acicular crystals. But the most accurate procedure is to digest 

 this thick liquid for a few minutes in alcohol, and to filter the 

 solution while boiling hot. After some hours it concretes into a 

 soft white coloured mass, resembling a cauliflower : this may be 

 rendered considerably purer by squeezing out the alcoholic liquid, 

 redissolving the solid portion, and crystallizing a second time. 



Thus obtained, it possesses all the properties of manna purified 

 by solution in alcohol. Like this, it has a sweet taste, is very 

 soluble both in cold and hot water, dissolves but sparingly in 

 cold, and to a large amount in hot alcohol, and on cooling sepa- 

 rates from the solution in the form of a soft white mass, resem- 

 bling a mushroom. The solution also is quite incapable of the 

 spirituous fermentation. 



The fresh leaves of celery yield rather more than one percent, 

 of manna, purified by repeated crystallization. 



He could not succeed in detecting a trace of manna in the 

 leaves of common parsley (Apium Petroselinum), or of the com- 

 mon leek {Allium porrum). 



This is the first well authenticated instance of manna occur- 

 ring in the leaves of an European plant. — (Schweigger and 

 Meinecke's Jahrbuch der Chemie und Physik, vii. 365.) 



* This is the name which l'elletier and Caventou have applied to the green colouring 

 matter of leaves, and which would appear from their experiments to be a peculiar vege- 

 table principle. — (See Journal de Pharmacie, iii. 486.) 



New Series, vol. viii. 2 c "* 



