ON IODIDE OP POTASSIUM. 
287 
times its weight of the muscular tissue of boiled beef, and 
much more rapidly than could be effected by the gastric 
juice itself. 
The term pepsine does not answer to apply to this active 
substance, since it is not only when the animal is hungry 
that it is secreted, but at the moment the aliment stimulates 
the stomach: for this reason I think proper to give to it the 
name of gasterase. 
If I do not now make known the means of extraction, it 
is in the hope to give them less imperfect, and to join to 
them the results of an analysis which may better determine 
the nature and limits of action of this active principle. A. D. 
Journal de Pharmacie. 
ART. LXXII. — ON THE ^REPARATION OF PURE IODIDE 
OF POTASSIUM. 
By Messrs. Thos. and H. Smith, Edinburgh. 
Op the value of the various processes which have been re- 
commended for the preparation of the iodide of potassium, 
in reference to their facility of preparation, economy, and 
suitableness for the production of a pure salt, we do not feel 
ourselves qualified to give an authoritative judgment ; we 
are, however, inclined to give the preference to that adopted 
by the Colleges of London and Edinburgh, which is grounded 
on the double decomposition of the iodide of iron by a so- 
lution of the carbonate of potash; but by proceeding in the 
way recommended by these colleges, a pure salt cannot be 
obtained, except by a tedious process of crystallization and 
recrystallization, or by dissolving in alcohol, and thus sepa- 
rating it from those impurities insoluble in that menstruum, 
