PREPARATION OF COLLODION, 
209 
peratures. The necessity of water being employed in the 
preparation of Camphorated Tincture of Soap, being ad- 
mitted on all sides, should not the quantity and mode of 
manipulation be distinctly set forth by our standard ? 
The quantity of water required has been variously esti- 
mated from a fourth* to a sixteentht of the menstruum 
directed. The Dispensatory indicates a little more than the 
sixth, and we have been informed by Prof. Procter that he 
employs a seventh* 
Another source of error may arise from the selection of 
the soap. It is now well understood that castile, or vege- 
table oil and soda soap is meant, but by not heeding the 
definitions in the Pharmacopoeia, connected with the two 
officinal soaps, a difficulty may occur as in the case of the 
late Mr. Buhamel, (see American Journal of Pharmacy, 
vol. 9, pp. 281.) 
ART. XLVL— OBSERVATIONS UPON, AND IMPROVEMENTS 
IN, THE PREPARATION OF COLLODION. 
By Charles S, Rand. 
All solutions of prepared cotton, now in use under the 
name of collodion, are liable to objection, on account of the 
powerful contraction which takes place during the evapora- 
tion of the ether, and formation of the pellicle. In certain 
cases this is its most valuable property ; but where merely 
a protecting envelope, or false skin is required and the 
surface to be covered is large, this contractility is an objection 
which has in many cases prevented its employment, and 
caused the substitution of preparations, in other respects 
* Revision of Pharmacopoeia by Committee of Philadelphia College 
of Pharmacy, 1830. 
f Remarks on Soap Liniment by Augustine Duhamel, American 
Journal of Pharmacy, vol. 15, p. 163. 
18* 
