& _ INTRODUCTION« 
deavour to attain an intimate acquaintance with the 
parts of the flower and fruit, (partes fructijicationis ), 
so as to be able to form distinct characters from 
these particulars; and, till he has attained this ac- 
quaintance, his knowledge cannot be said to rest om 
scientific principles. ‘To derive the proper advantage 
from such knowledge, he must endeavour to im- 
print the form of the plant upon his memory. But 
as from the immense number of plants this is almost 
impossible, and often at particular seasons of the year, 
plants which we would wish to compare with one 
another are not to be found, we must endeavour to 
assist ourselves by a collection of dried plants, ( Hor- 
tus siccus, Herbarium). The rules to be observed in 
forming such a collection are the following. 
1. The plant is to be laid between folds of blos- 
som paper, the parts of it properly spread out, and 
the paper often changed, that the plant may not 
shrivel or become black: this is to be done in a 
moderately warm place, where the sun enters freely 
and the current of air is not interrupted. 
2. In drying the plant we must take care to give 
the parts no direction which is unnatural to it; for 
instance, we must not give to a fower, which natu- 
rally hangs down, an erect position; flower-stalks 
that are attached to one side must not be turned to: 
both, a bent or procumbent stem, must be preserv- 
ed in that state, &c. 
3. The plants must be gathered at that particular 
time when they possess all the characters by which 
they are distinguished from others. If the differ- 
ence 1s found in the root, in the radical leaves, or in 
the 
