FRANCIS WILLUGHBY. 
35 
in order to meet what is called by Cicero “ the 
insatiable variety of nature 5 ” that it can exhibit 
only disjointed parts of the universal frame of 
being. On the whole, an artificial system is best 
adapted for use, while a natural system alone can 
enable us to know the probable station of any 
creature in the system of the scale of being, by 
the affinities it possesses to others, and the ana- 
logies by which it is related and represented. 
The attainment of the best natural system is, 
however, likely to follow from the inquiries made 
by the best artificial systems. 
The first formation of an artificial system, 
when all circumstances are considered, will ever 
be regarded as an interesting epoch in the annals 
of science. It is now intended to contemplate 
that event as it is presented in the history of 
Aristotle. Scarcely any thing is known with 
certainty of the early life of this illustrious man, 
except that he studied at Athens with the most 
intense assiduity under Plato, and that this 
eminent philosopher used to call him “ the mind 
of his school and when Aristotle was not there, 
to say, “ The soul of the school is absent.” 
Some time after the death of Plato, which 
happened about the year 348 n.c. and when 
Aristotle was thirty-six years old, he began to 
teach publicly at Athens ; and after having gained 
the highest celebrity as an instructor of youth, 
he was invited by Philip, king of Macedon, to 
undertake the education of his son Alexander, 
then about fifteen years of age. The letter in 
