ON THE CONSTRUCTION OF A PHARMACOPEIA. 
565 
characteristics corresponding thus closely, it was thought probable that the 
active principles of scammony and jalap are identical, particularly as the plants 
yielding them belong to the same Natural Order. 
ON THE CONSTRUCTION OF A PHARMACOPOEIA. 
B'Y PROFESSOR REDWOOD." 
It is probable that, before long, a new edition of the British Pharmacopoeia 
will be produced, and it is very desirable that whatever means may occur to 
those most interested in the subject for increasing the usefulness and value 
of the work, should be pointed out and discussed before the new Pharmaco¬ 
poeia is committed to the press. With the view of promoting this object, I 
venture to submit a few points for discussion this evening. 
1. Arrangement and Classification of Matter .—In looking at the Pharmaco¬ 
poeia for the purpose of considering what changes may with advantage be made 
in a future edition, the first and most obvious character that presents itself to 
notice is that of the arrangement of matter and the general construction of the 
work. Viewing the Pharmacopoeia as a medium of communication between 
prescribers and dispensers of medicine, as the authorized exponent of the value 
and meaning of the terms to be employed in extemporaneous prescriptions, it is 
important that it should not only supply the required information, but should 
admit of easy reference, and that all the information it may be thought neces¬ 
sary to give relating to any article, should be presented at once in a connected 
form to those who have occasion to seek it. The division of the Pharmacopoeia 
into two parts, one containing the Materia Medica, and the other the prepara¬ 
tions and compounds, is an arrangement, as adopted in modern Pharmacopoeias, 
that is neither correct in regard to classification, nor convenient in practice. 
Strictly speaking, the preparations and compounds belong to the Materia Medica 
as much as do the articles used in producing them ; and while the term Materia 
Medica is thus incorrectly restricted to the substances hitherto described under 
this head in our Pharmacopoeias, it may equally be said that many articles in¬ 
cluded in the Materia Medica belong to the class of Preparations and Compounds. 
If we turn to the early Pharmacopoeias of the seventeenth century, we find that 
the substances comprised under the head of Materia Medica were, with very few 
exceptions, natural products, not in a fit state for administration in medicine, 
and requiring preparation in a variety of ways to render them suitable for that 
purpose. But the Materia Medica part of our Pharmacopoeias has long ceased 
to consist merely of a list of crude drugs. Many medicines prepared for use 
have from time to time been transferred from the second to the first part of 
the work, and this has been promoted by the extension of chemical manufac¬ 
tures, which has caused many chemical compounds to be produced in a state of 
greater perfection, and more economically on the large scale, than they could be 
by those who use them in dispensing, so that it has been thought desirable to 
omit the processes for such compounds and to include them in the Materia 
Medica. 
In several of the recent foreign Pharmacopoeias, such as the Pharmacopoea 
Borussica, Pharmacopoea Austriaca, and Pharmacopoea Norvegica, all the arti¬ 
cles ordered, excepting those to be used as reagents or tests, are included in 
one category, and are arranged there in alphabetical order. This appears to me 
to be not only the most simple, but in every respect the best arrangement for a 
Pharmacopoeia. It obviates all difficulties of classification, and presents the 
greatest facility that can be afforded for reference. The work is used like a 
dictionary, and is its own index. Every article is described under its proper 
