4 THE MISSION OF PHARMACOGNOSY. 
practicable to do this, without resorting to an actual chemical 
analysis. In an accurate knowledge of the nature of medicinal 
substances lies, indeed, the best protection against substitution 
and adulteration. 
The most important property of medicinal substances, how- 
ever, is their medicinal action, yet this must remain excluded 
from pharmacognostical consideration, for it has become the 
subject of an independent scientific discipline, viz., pharma- 
cology. From apparent practical reasons it will, indeed, occa- 
sionally be found advisable, especially in the case of particularly 
interesting substances, to at least allude to their therapeutic 
action. That these two domains present many points of contact, 
and that pharmacology receives especial support from scientific 
pharmacognosy, in fact, that it presupposes a knowledge of the 
latter, is clearly evident. In England, France, and other coun- 
tries, the two expressions, Pharmacology, which treats of the 
therapeutic action of medicinal substances, and Pharmacognosy, 
which comprehends a scientific knowledge of the substances 
themselves, are occasionally employed in a sense different from 
that which has just been indicated. It must be admitted that 
the tenor of the two words expresses no sharp distinction.* 
With regard to the chemical side of pharmacognosy, it is 
necessary to restrict it within certain limits. It is doubtless 
quite as appropriate that the properly isolated constituents of 
drugs should be enumerated and characterized, as that it should 
be stated, or at least intimated, where material deficiencies occur 
in this direction, which it is desirable to supply. An exhaustive 
treatment of the chemical constituents, however, falls within 
the domain of chemistry, or pharmaceutical chemistry. 
' Schmiedeberg, in his ‘‘ Grundriss der Arzneimittellehre,” Leipzig, 
1883, says: ‘‘ The science which treats of medicinal substances (Arznei- 
mittellehre) has only to do with such agents as are useful in the curing 
of disease. It is, therefore, desirable that all substances which do not 
serve as food, and which, through their chemical properties, produce 
changes in the living animal organism, should, in order to investigate 
these effects, be brought within the borders of a single science, which 
may be called Pharmacology, or, since it is chiefly supported by experi- 
_ ment, Experimental Pharmacology - 
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