PREPARATION OF CALOMEL. 
89 
ART. XIX. — PREPARATION OF CALOMEL IN A STATE OF 
MINUTE DIVISION. 
BY M. SOUBEIRAN. 
Both medical experience and chemical science tend to 
prove that the minute division of calomel adds to its medi- 
cinal energy. Porphyrization is not sufficient to effect this 
purpose, it affords a yellow powder, which is never suffi- 
ciently impalpable. Joseph Jewel was the first who disco- 
vered another method of pulverization. He proposed to 
conduct the vapour of calomel into a vessel containing 
water in a state of ebullition, and the steam from the latter, 
mixing with the vapour of the calomel, caused its speedy 
aggregation in the form of an impalpable and uniform 
powder. 
If this process of Joseph Jewel's be not absolutely im- 
practicable, it is at least very difficult to perform, hence all 
those who have attempted to apply this process, have soon 
given it up. In 1822, M. Henry, convinced from practical 
experience that he could never arrive at any satisfactory 
result by adhering strictly to Jewel's process, suggested a 
modification of the apparatus, which has been introduced 
into our laboratories, and is mentioned in most Pharmaceu- 
tical treatises. M. Henry's modification of the process 
consisted in having the steam generated in a separate vessel 
from that into which the vapour of the calomel is conducted. 
It is unnecessary to describe here the precautions which 
were necessary in conducting this process; it is sufficient 
to say, that those who have adopted this process, have 
found many practical difficulties, and not the least frequent 
has been the fracture of some of the vessels employed. 
This process, notwithstanding its difficulties, being the 
only one employed in our laboratories, the practice has be- 
