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PHARMACOGNOSY. 
(4) Biological methods involve the consideration of 
the effects of drugs upon animals or plants. They 
may be conveniently grouped as follows: I. Effect or 
influence upon animals ; (a) depending upon the percep- 
tions or senses of the experimenter or tester ; ( b ) de- 
pending upon the physiological or pathological effects 
upon lower animals, as insects, frogs, rabbits, guinea 
pigs, etc., and even man. II. The effect or influence 
upon plants, depending upon the effects of extracts of 
drugs, or tolutions of their active principles upon ger- 
minating plants, this being estimated by the amount of 
growth of the root of the plant placed in the solution, 
in a given time, or by the changes in the tissues. 
B. DRUGS DERIVED FROM FLOWERING 
PLANTS. 
I. SEEDS. 
From an economical point of view seeds, both as re- 
gards their medicinal properties and the food products 
which they yield, constitute a most important group. 
They should, as a rule, be collected when they are ripe 
and carefully preserved against the attacks of insects 
and changes of various kinds, as those incident to ger- 
mination. They may, or may not, be dried before 
using. 
For convenience in their study, as well as their rec- 
ognition, the medicinal seeds may be classified as 
follows : 
I. ENTIRE SEEDS. 
I. Not more than 5-6 mm. long. 
1. With an appendage ( caruncle ) : 
a. Ovoid or irregularly globular, dark brown, 
Colchici semen 
2. Without an appendage : 
A. Anatropous. 
a. Ovate, flattened, smooth Linum 
b. Triangular or quadrangular, reticulate . . Staphisagria 
