66 PREPARATION OF THE JUICE OF DANDELION. 
until it be reduced to one-half. We now have the salts, (which 
in a medical point of view are of great importance) and other in- 
gredients^ a much more concentrated form than in the original 
juice, but the bitter principle has been somewhat impaired in effi- 
cacy during the evaporation. Even if this deterioration had not 
taken place, the juice does not in its natural state contain a suffi- 
cient ratio of the bitter principle to act with adequate effect as a 
tonic when so moderate a bulk of the liquid is administered as is 
convenient or suitable. On this account a quantity of roots with- 
out leaves, equal to the weight of whole herb previously employed, 
must be pounded and expressed. This bitter juice, which is very 
small in quantity, not in some seasons more than a gallon from 
112 pounds, is to be laid aside until the residual marc, from which 
it has been pressed, has undergone a new process, which is as fol- 
lows : The mixture of juice obtained from the whole herb and the 
evaporated infusion of its marc is again to be brought to a boil, 
and at that temperature is to be infused on the marc of the roots ; 
the temperature will thus be reduced below the injurious degree, 
but will be still sufficient for extraction of the bitter. When cold 
the liquor is to be strongly pressed out, and mixed with one-sixth of 
its total measure of spirit of wine. The mixture is to be poured into 
common quart bottles, but they are not to be entirely filled. Ap- 
pert's process somewhat modified, must now be resorted to. A 
large shallow vessel containing cold water is to be placed on a 
fire: the nearly filled bottles are to be immersed in the water as 
high as the liquor within : the water is to be slowly brought to 
about 180° : the bottles are to be withdrawn, and the reserved 
juice obtained from the roots is to be added to each in equal quan- 
tities. These quantities ought to fill the bottles so high in the 
neck that when the corks are driven in there will be the smallest 
possible intervening space. The corks being cut off close to the 
glass, the mouths are to be sealed with hard bottle wax : and the 
bottles set by, inverted, in a cool place. 
" The bitter principle, obtained in the second part of the pro- 
cess, having been scarcely exposed to heat, is as perfect as it ex- 
isted in the roots. Heat is highly injurious to the active principle 
of various vegetable substances. The root of Arum maculatum is 
so poisonous and so acrid that it will blister the skin; but by boiling 
and even drying it becomes harmless, and in that state is by some 
