290 Dr. Hare’s method of detecting Opium. 
The old method of preserving snakes in spirits is too ex 
pensive, and requires too much attention, to be recommended, 
and stuffing is preferable to it in every respect. Such sub- 
jects as have been in spirits for a length of time may still be 
thus treated, only 1 in this case, they, as well as other animals 
that have been in spirits any time, are not stripped with as 
great ease as more recent specimens. The skins of all am- 
ptibia, procured in tr avelling in foreign parts, which would 
take too much time to be immediately stuffed, and too much 
space in packing, may be dried inside out and then packed 
up together. The skins of snakes may be easily rolled, but 
those of frogs and lizards should be pressed flat. en you 
intend to fill them, steep them first in water, throwing it off 
and pouring fresh on them from time to time to guard against 
putrescence. 
As soon as they have become perfectly pliable, you may 
fill them without trouble, and they will look as well as those 
that have been fresh skinned. 
‘Art. XL—A ‘method of detecting minute quantities of 
Opium, in solution; by ROBERT eas . D. &e. 
Trove the discoveries of Seervemnen, it is now well 
nown, that opium contains an sear substance, called 
morphia, to which it owes its efficacy in promoting sleep, 
and relieving pain: also, that this alleali i is naturally in union 
wiih an acid called meconic, which produces a striking red 
colour, with solutions of red oxyd of iron. Nevertheless, 
this property has not been proposed asa means of detecting 
opium ; which has prebably arisen from the circumstance that 
the meconate of iron does not precipitate. 1 have, however, 
contrived a method by which a quantity of opium, not ex- 
ceéding that contained in ten drops of laudanum, may be de- 
. tected ina half gallon of water. 
= My 8 ate is founded on the property which meconic acid 
has of precipitating with lead. Hence, by adding a few 
S of acetate of lead to any infusion, containing any 
ity of the drug in question, not more minute than the 
on above mentioned, an observable quantity of the 
meconate of lead falls down. The precipitation, where the 
