PREPARATION OP MERCURIAL OINTMENT. 
219 
before. This explains at once why, in certain judicial 
investigations, arsenic has been sought for in vain in the 
liquid portion of the food contained in the stomach, when 
the food partly consisted of fatty substances, such as broth, 
milk, &c. It likewise explains how arsenious acid, taken in 
powder, may sometimes have sojourned a long time in the 
stomach before it produced any deleterious effect, since in 
such cases its action was hindered by the presence of fatty 
substances. Jugglers have been seen swallowing arsenic 
with impunity, because, according to Dr. Blondlot, they had 
previously taken the precaution to drink milk and eat fat 
bacon. Hence it follows that in cases of poisoning by 
arsenic, fatty substances may be administered as real an¬ 
tidotes, capable of suspending the action of the poison for a 
considerable time, until more radical means of effecting a cure 
can be applied .—Medical Times and Gazette . 
PURIFICATION OF CASTOR-OIL. 
When castor-oil has become thick and rancid by long 
keeping, it may be purified, according to M. Parnesi, of 
Turin, by mixing 1000 parts of the oil with 2 of animal 
charcoal and 10 of magnesia, stirring the whole frequently 
together for three days in a temperature of from 68 to 70. 
After which it is to be passed through a filter. 
PREPARATION OF MERCURIAL OINTMENT. 
M. Delarue considers the presence of water in lard mate¬ 
rially interferes with the making of mercurial ointment. He 
therefore heats the lard up to 125° or 130° C., so as to expel 
the water from it, and sets it aside for three days. After 
which he mixes the whole of the mercury with one third of 
the lard, and then gradually adds the remainder. Subse¬ 
quent trituration for two hours suffices to perfect the making 
of the ointment. 
