MISCELLANY. 
Detection of the presence of Potato Starch in the Powder of Rice or Ar- 
row-root, by means of Diluted Hydrochloric Acid. By M. Scharling. — 
If powdered rice or potato starch be mixed with concentrated hydro- 
chloric acid, in the proportion of about one part of the former to one and 
a half or two parts of the acid, they form almost immediately a thick 
mucilage. The mucilage of potato-starch is nearly transparent ; that of 
the rice, on the contrary, is opaque. They both emit the odor of formic 
acid. 
If a mixture of hydrochloric acid and water be used, a very different 
action is exercised on the two substances already named. The potato 
starch forms, in a very short time, a mucilage so thick, that the morter 
may be lifted up by means of the pestle used in making the mixture; 
while the powdered rice does not acquire a similar viscosity in less 
than twenty-five or thirty minutes. If the rice-powder contains from 
four to six per cent, of potato-starch, it is easy to detect the admixture 
by means of this re-agent. For this purpose] a mixture of equal parts 
of hydrochloric acid of commerce and water should be used. 
Arrow-root comports itself in the same manner as rice-powder, with 
the hydrochloric acid, while wheat-starch resembles potato-starch in 
this respect. 
M. Marezeau, as is known, has proposed hydrochloric acid as a means 
of detecting potato-starch in flour, by the strong smell of formic acid 
which it developes in contact with the acid ; but as the same effect is 
produced, in this respect, with rice-powder and arrow-root as with po- 
tato-starch, the hydrochloric acid cannot be used in this way for de- 
tecting the admixture of these latter. — Pharm. Journ. and Trans., from 
Anal en der Cheraie und Pharmacie. 
On the Danger of Keeping Milk in Vessels of Zinc. By Dr. 
Elanes, of Berlin. — I scarcely could have believed that zinc vessels 
could again have come in use for keeping any fluids used for alimentary 
purposes, as Vauquelin proved, forty years ago, that such will contain, 
