COLLODION AS A COATING FOR PILLS. 
183 
gists in London yielded, in 100 grains, Si grains of sulphate 
of lime (gypsum.) 
As cream of tartar is the source to which the chemical 
student is generally referred for pure carbonate of potash 
the exposure of this fraud becomes doubly important.— Ibid. 
ART. XLI.-COLLODION AS A COATING FOR PILLS. 
By Mr. E. H. Durden. 
I find that collodion may be usefully employed for coat- 
ing pills; for this purpose the pills may be placed on the 
point of a fine pin or needle, and dipped into the solution 
of gun cotton. The solution I used had a sp. gr. of 0.810, 
and I found two dippings gave a perfect coating. An aloetic 
or colocynth pill thus covered may be placed on the 
tongue, and no taste experienced of the bitter ingredients 
entering into its composition. Its medicinal effect is not 
interfered with. Solutions of gutta percha in chloroform, 
and bisulphuret of carbon, effects the same purpose, but the 
collodion is preferable. — Ibid. 
ART. XLIL— METHOD OF DETECTING THE FLOUR OF 
INDIAN CORN IN THAT OF WHEAT. 
By M, Mauviel la Grange. 
The sample is sifted, and 2 grms. of the finest flour mixed 
jn a test-tube with four grms. of nitric acid, and well stirred 
with a glass rod. After this add 60 grms. of water, and 
then 2 grms. of carbonate of potash dissolved in 8 grms. 
water. When no Indian corn is present, as soon as the 
carbonic acid has escaped, only yellowish flakes separate ; 
