278 
HISTORY OF BOTANY. 
admitting that the only sure method of leariiig nature was to 
study her works, that the labours of philosophers began to be 
followed by important discoveries. 
The greater part of the ancient Greek philosophers asserted, 
that plants were organized like animals, that they possessed 
sensible and rational souls, capable of desires and fears, pleasure 
and pain. Pythagoras of Samos, who travelled in Egypt, and 
was there instructed by the priests of the goddess Isis, is said by 
Pliny to have been the first of the Greek writers who composed 
a treatise on the properties of plants. 
Seven men of the name of Hippocrates, wrote upon the me- 
dicinal properties of plants ; but their descriptions, being desti- 
tute of system, are vague and cannot be applied to plants with 
any degree of certainty. 
Aristotle, perceiving that that the course taken by preceding 
philosophers had not conducted them to the true knowledge of 
things, partially renounced their false ideas, and rested more 
upon observation and experience. In his researches he was 
favoured by Alexander of whom he had been the preceptor. 
That conqueror, in the midst of pride and the fury of passion, 
still possessed the love of true glory, and a desire that his con- 
quests might serve to promote the improvement of the human 
mind ; he allowed to Aristotle, in the prosecution of his scien- 
tific investigations, every facility that wealth and power could 
bestow. 
Aristotle believed, that in nature there was a regular progress, 
from inorganized matter upwards to man, and from man upwards 
to the Deity ; that beings were connected together by certain 
affinities, composing an immense chain of which the links were 
all connected. Thompson seems to have had this idea in his 
mind when he wrote thus: 
“And lives the man whose universal eye 
Has swept at once the unbounded scheme of things ? 
Has any seen 
The mighty chain of beings, lessening dowij 
From infinite perfection to the brink 
Of dreary nothing, desolate abyss ! :l 
This idea of a regular chain of beings, presenting itself with 
such grandeur and simplicity, has had many admirers; but facts 
do not always seem to correspond with this theory. In the 
vegetable kingdom we should find it impossible to trace a regu- 
lar gradation from the oak to a moss, (if we were to make these 
the extremes of the chain of vegetable substances,) and say ex- 
actly in what part of the scale each family of plants should be 
Pythagoras — Hippocrates — Aristotle — 
