AN ESSAY ON LACTUC ARIUM. 
37 
evidently, the one I ought to prefer. In fact it is only ne- 
cessary to place the lactucarium over the fire, until 32 parts 
of distilled water have boiled, to extract 60 per cent, of its 
weight, by squeezing the residue in a fine cloth. 
The liquid thus collected is extremely bitter, slightly 
cloudy, and tolerably colored. The substance it leaves in 
the capsule has all the characters of the preceding. It has a 
reddish color, semitransparent when in thin flakes, and isin- 
supportably bitter. Boiling distilled water, in sufficient 
quantity, dissolves the greatest portion instantaneously, and 
keeps the remainder suspended. The liquid, as it becomes 
cold, becomes a little clouded, but deposits scarcely any- 
thing. This desposit is slightly colored ; but it is of little 
consequence, its quantity being so extremely small. 
If we treat the insoluble residue with a fresh quantity of 
boiling distilled water, we find the same weight after it is 
perfectly dry. It is the same when this body is macerated 
in alcohol ; let the density of the liquid be either weak or 
strong, 21 or 36 degrees, the residue remains untouched. 
Sulphuric ether, alone, has an action, and a powerful action, 
on this residue. It carries off more than four fifths^of its 
weight of the white substance already noticed, but to pro- 
duce this effect maceration of 12 hours duration, at least, 
are necessary ; a third has scarcely any result. The ethe- 
real liquids, the first particularly, is of a strongly marked 
bitter taste, which gives us reason to suspect the presence 
of a small quantity of the active matter. Still we must 
only to a certain extent take this bitterness into account, 
for we ought not conceal from ourselves that ether itself is 
sensibly bitter. 
In addition to this, we may remark, that all these ex- 
tracts, the aqueous extract in particular, on which heat has 
had most influence, possess in a very slight degree only the 
poisonous smell that so well distinguishes lactucarium. 
This appears to me to prove clearly enough, that the 
poisonous principle, on the importance of which we must 
VOL. XII. — no, i. 4 
