590 
ON SILITIIUM, Oil ASSAFCETIDA. 
Mediterranean, secretes a gam resin, which flows from incisions made in the 
stem, and used to be known as Sicilian bdellium. 
Pastinaca saliva , when in its native condition, contains a very acrid sap, 
which entirely disappears on cultivation ; while specimens of Conium maculatum , 
obtained near Edinburgh, have been found comparatively harmless, the narcotic 
acrid principle, from the effects of soil or cultivation, having become latent. 
Such, in theory, are our ideas on the true classification of the properties of the 
plants of the Umbelliferx. 
Further on, we read, on the subject of the extraction of the active principle 
of the aromatic plants:— 
“ To obtain this active principle, in the state in which it exists naturally, we make 
an alcoholic extract of the fruit, this is to be then treated with ether or chloroform ; a 
product is thus obtained, without the use of any active reagent capable of injuring its 
quality. We thus have a group of substances resembling apiol in their physical and 
chemical characters: anisol, curiol, cuminol, are obtained respectively, as thick, yellow, 
strong-smelling oils, liquids from the anise, carraway, and cumin.”- 
The chapter on the gum-resins is interesting; on the subject of their first 
state as latex, which he compares to lymph, contained in the lymphatic vessels 
of animals, the author considers that— 
“ The formation of the milky juices is due to the presence, in the laticiferous 
vessels, of water, holding in suspension essential oil, caoutchouc, resin, and gum; the 
successive oxidation of each of the first two bodies producing gum. 
“We find, in all plants,— 
“ Gum, which seems to be assimilated cellulose. 
“ Resin, a product of the oxidation of the fatty bodies. 
“ Fatty bodies, fixed or volatile oils and caoutchouc, containing little or no oxygen. 
“ Gum can thus be considered the extreme term of this series of bodies differently 
oxidized, of which the fatty bodies form the point of departure ; and the union of these 
three bodies, fonning an emulsion with water, give the milky juices in question. 
“ The latex is found in the outer stem and leaves, and being in continual contact with 
the oxygen of the air, its elements are thus in a condition to undergo the transfor¬ 
mations to which I have just referred. In spring the changes take place very rapidly ; 
towards autumn the juices become milky, and contain less water.” 
The author thus considers the fixed and volatile oils to be the point of de¬ 
parture in these changes in the latex ; most botanists think them the highest or 
extreme product of vegetable life, and prove it by their presence in the seed, 
the last formed organ in the plant. This latter objection is here simply ex¬ 
plained by comparing the fatty bodies or essential oil in the seed to the pro¬ 
vision placed among their eggs, to supply with nourishment the young larvse on 
their first appearance. 
The purification of gum-resins is a difficult process ; heat is employed in all 
formulae, and this more or less dissipates the volatile oil contained in them ; the 
heat employed in their pulverization is especially to be blamed ; the necessity, 
however, for any method of purification is obviated by the use of the gum-resins 
in pure guttx. This the author thinks the only way to have an article at the 
same time pure and perfectly efficacious. 
Speaking of emulsions, a curious process is mentioned, though with disap¬ 
probation :— 
“ One part of the gum-resin is placed in a mortar with four parts of alcohol; the 
latter is set on fire, and the whole rubbed down until the flame dies out; the product is 
a soft extract, forming with, water a perfectly homogeneous emulsion.” 
However the conclusion shows a trait of humour :— 
“ It is evident that the gum-resin must be seriously altered by this operation, not a 
very practical one for the dispenser, whose fingers would have to be exposed to a heat 
somewhat abnormal.” 
