THE SEQUOIA 
advanced the study of anatomy by his careful dissections of apes 
and some of the lower animals, and he also wrote extensively on 
physiology; but accurate as some of his observations were, his 
errors, particularly in physiology, were many. His works, how- 
ever, remained authoritative for fully 1400 years; his statements 
overruled the demonstrations of nature, and he was so reverenced 
that whoever had the courage to dispute him was liable to per- 
secution and ostracism. 
Physiology was not materially different from metaphysics, 
and both were affected with superstition. The ancient belief that 
the body contained four humors—‘ blood,” “phlegm,” “yellow 
bile,’ ‘‘ black bile’’—was held, and Galen had added to these a 
‘““pneuma,’’ which pervaded the whole body, mingling with the 
humors and supporting life. The proper mixture of four ele- 
ments—heat, cold, wetness and dryness—constituted the normal 
individual. The administration of drugs was in accordance with 
this belief. Systematic zodlogy did not exist. There was no true 
conception of species, no-accurate description of animals, and no 
adequate system of classification. The naturalists were merely 
compilers and copyists of Aristotle and other ancient writers. 
The philosophical or speculative in biology was retained by 
the clergy, almost the only persons really interested in the conser- 
vation of documents, and asa class the only ones able to read and 
write. 
Some of the Greeks had had explanations of the succession of 
organisms on the globe. Aristotle believed that the first animals 
arose from the ocean, and that low forms of life were constantly 
springing into existence by spontaneous generation, a fallacy 
which was not completely rooted out of biology until the nine- 
teenth century. Aristotle also perceived the principle of adap- 
tation in nature, and considered the universe as the result of 
Intelligent Design. These ideas of the Greeks had a marked 
influence on Christian thought for many centuries. Augustine 
(fifth century) believed that a living substance had been made 
by the Creator, and that from this had developed all the diverse 
‘organisms of the present time. Two other famous churchmen 
advocated similar views, Erigena in the ninth century, and 
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