715 
or THE BRITISH PHAllMACOPCEIA, 1864 AND 1867. 
o. Exposed of the “Succus” upon a plate in a glass-house with a south 
aspect, and where the natural temperature ranged from 70° to 90° Fahr, After 
thirty-four hours the small syrupy residue was treated with potash and washed 
with aether; 0'25 of a grain of conia was obtained. 
Two facts ajipear from these experiments—first, that the active principle of 
the plant is to a certain extent vaporizable even at a natural temperature of 70° 
to 90° Fahr. ; and secondly, that prolonged exposure to a high temperature is 
accompanied by a progressive diminution of the conia, the alkaloid being con¬ 
verted, as Dr. Christison has pointed out, into ammonia and some other se¬ 
condary product. 
Now the quantity of juice prescribed by the Pharmacopoeia for conversion 
into extract, is about eight gallons, and the prolonged exposure to a tempera¬ 
ture ranging from 140° to 212° Fahr., required to effect this process, is doubt¬ 
less sufficient to remove all but a trace of the active principle ; and it is obvious 
from the foregoing that, given an efficient juice, the power of the extract will 
be inversely proportionate to the bulk of the juice operated upon ; hence, to ob¬ 
tain an extract of full power, it will be necessary to expose the juice in a number 
of shallow dishes, and in a layer not exceeding half an inch in depth, to a rapid 
current of dry air having the temperature of 150° Fahr. or thereabouts, so that 
the whole may be reduced to the consistence of an extract in the course of 
two or three hours. By this means an extract, containing 1 per cent, of conia 
at most, may be procured. And it is extremely doubtful whether a stronger ex¬ 
tract can be prepared by this or any other process. 
Such are the conclusions to which the foregoing experiments lead, and in re¬ 
spect of the use of the extract they are important. One fact is quite certain, 
viz. that the power of the extract has been greatly over-estimated. The present 
Pharmacopoeia (1867) directs it to be given in doses of from 2 to G grains. 
Now, granting that this preparation retain the whole of the active principle, 
which, from my examination of the “ Succus,” I place at IT grain in a 100 
grains ; 6 grains of the extract would represent only the 0 084 of a grain of 
conia,—a quantity insufficient to j)roduce the effects of hemlock in a child two 
years old. The physiological action of hemlock is such, that doses which fall 
far short of producing it are of no use; and it is doubtful whether the possession 
of an extract containing 1 per cent, of conia—which I believe is the strongest 
that can be made—will be of any advantage, since 25 grains of it would be equi¬ 
valent to only f 5 iv of the “ Succus'' of the Pharmacopoeia. 
It has been doubted by some wh'ether the Athenian state-poison was wholly 
derived from the hemlock; I see no reason myself—on account of the expres¬ 
sion “ ixLKpov Trduv KaraTvoriov^ a very little dose —for doing so. The inspissa- 
tion of the juice was effected, according to Dioscorides, by exposing it to the sun ; 
and by this means a syrup may be prepared, of which, assuming the Greek 
plant to be equally powerful with that grown in these temperate regions, a tabic- 
spoonful or two would doubtless prove a fatal dose. 
I will conclude these remarks by the following particulars, which will serve to 
render my account of the Succus Conii, No. 1, upon which I have chiefly based 
my experiments, more complete, f ^j of the “ Succus" yields six grains of white 
ash, which fuses with effervescence before the blow-pipe into a porcellaneous 
mass, dissolves witli copious effervescence in the mineral acids, and the clear 
acid solution gives an abundant heavy yellow crystalline precipitate with bi¬ 
chloride of platinum. Hence it follows, that the juice contains one or more 
vegetable acids and potash. 
It is to be observed that Schraderf makes no mention of either soda or sugar 
* Theofrastos, Hist. Plant, iv. viii. p. 298, ed. Schneider, 
f Berzelius, ‘ Traite de Chimie,’ vol. vi. p. 251'. Berlin. Jahrbuch, 1805, s. 152. 
3 B 2 
