ON THE KXTKACT OF RHATANY. 
271 
bark; and consequently, in choosing the root, attention should 
be given to this circumstance, — the smaller roots containing 
the largest proportion of bark, and consequently the most 
activity. 
As the ready performance of an operation is a feature of 
great importance in causing its general adoption, the difficulty 
of reducing rhatany to that state of division absolutely neces- 
sary to its use in the method of displacement, is a great bar- 
rier to the adoption of that method in the formation of the 
extract. Now this difficulty is altogether due to the woody 
portion of the root, which is extremely tough and difficult to 
reduce. In consideration, therefore, of the large proportion 
of cortical portion, of the ease with which it is separated, and 
of the large product which it yields, it is now suggested, that 
in preparing the extract the bark only be used, which is 
readily powdered. 
If we suppose that the root is composed of equal parts of 
wood and bark, then 
50 parts of bark yield 16.5 parts of extract. 
50 " wood " 3.5 " " 
100 " root " 20. " " 
Now it would be far better that the operator should wholly 
reject the ligneous portion, or at least treat it separately, than 
by a resort to boiling, to injure the whole product; for it has 
been clearly shown, that while the gross amount of extract 
obtained by boiling is the largest, its soluble and really active 
portion is much the least. 
But a serious difficulty to overcome in procuring the general 
adoption of a process, the product of which is improved in 
quality at the expense of its quantity, is the cupidity of the 
manufacturer; and whilst the self-interest of the pharmaceu- 
tist is prized higher than the welfare of the patient, the greater 
product will be chosen and the better rejected. The extract 
of rhatany, which entered into the composition of an extem- 
poraneous mixture, has been known to almost entirely preci- 
pitate, when the mixture was allowed to rest for a short time, 
even when care had" been extended, owing to the insolubility 
