VEGETABLE ALKALOIDS. 
36 ? 
diversion to the kidneys. Such views, it appears from the 
paper referred to, cannot be now entertained, aloine not 
being very active when given alone or unchanged. And this 
statement made by M. Robiquet is borne out by the article 
already referred to. It is only when this principle has become 
oxidized, that it can be said to possess any purgative pro- 
perties whatever, and this may be brought about in various 
ways, such as by the union of oxides, and especially by the 
action of air and heat. 
Doubtless an analogous conversion is effected in it as it 
passes through the alimentary canal ; this differing in degree, 
depending on certain circumstances, and hence the variable- 
ness of its effects as a purge. 
For our own parts we have long been advocates for the 
natural combination as it exists in certain plants, obtaining the 
principle by simply expressing the juice from the vegetable, 
then evaporating to a certain consistence, and preserving the 
same by the aid of dilute alcohol. But all our medicinal 
plants are not indigenous, and, therefore, we are more or less 
dependent on foreign sources for furnishing us with many of 
them ; and these being, of course, in a dry state, then it is that 
the science of chemistry steps in and separates the more active 
from the less active parts, giving to us agents of great 
power when judiciously employed. Nevertheless, until some 
more facile and less costly mode of obtaining the alkaloids 
be resorted to, we feel assured that as a class they will not be 
generally used in veterinary practice; although a few of 
them, from their potency, may be employed. 
Some persons have preferred the seeds of plants as thera- 
peutics, since they are less liable to variation in their 
composition, and the processes by which they are perfected 
are performed by nature herself on fixed and uniform 
principles. They are also less dependent for preservation on 
the artificial modes of drying, which are necessarily had 
recourse to for other parts of the plant, and consequently 
they are not so apt to become decomposed. Many of them, 
likewise, contain more of the active principle of the vegetable. 
This much is certain, that the processes for the procuration 
of pharmaceutical compounds from vegetables cannot be too 
simple. Either the expressed juice, or the pulverized leaves, 
or seeds, or roots, being employed ; for even the formation 
of a tincture, valuable as this form is, will sometimes change 
the mode of action of a vegetable substance. Still the 
addition of alcohol, as a preservative, may at times be found 
necessary. 
Mr. Bentley, pharmaceutical chemist, has proposed a plan 
