24 BIOLOGY AND ITS MAKERS 
the second century of the Christian era. He was a man of 
much talent, both as an observer and as a writer. His de- 
scriptions were clear and forceful, and for twelve centuries 
his works exerted the greatest influence of those of all scien- 
tific writers. In his writings was gathered all the anatomical 
knowledge of his predecessors, to which he had added ob- 
servations of his own. He was a man of originality, but not 
having the human body for dissection, he erred in expounding 
its structure ‘‘on the faith of observations made on lower 
animals.”” He used the right method in arriving at his facts. 
Huxley says: “No one can read Galen’s works without being 
impressed with the marvelous extent and diversity of his 
knowledge, and by his clear grasp of those experimental 
methods by which alone physiology can be advanced.” 
Anatomy in the Middle Ages.—But now we shall see how 
the arrest of inquiry already spoken of operated in the field 
of anatomy. The condition of anatomy in the Middle Ages 
was the condition of all science in the same period. From 
its practical importance anatomy had to be taught to medical 
men, while physics and chemistry, biology and comparative 
anatomy remained in an undeveloped state. The way in 
which this science was taught is a feature which characterizes 
the intellectual life of the Middle Ages. Instead of having 
anatomy taught by observations, the writings of Galen were 
expounded from the desk, frequently without demonstrations 
of any kind. Thus his work came to be set up as the one 
unfailing authority on anatomical knowledge. This was in 
accord with the dominant ecclesiastical influence of the time. 
Reference to authority was the method of the theologians, 
and by analogy it became the method of all learning. As 
the Scriptures were accepted as the unfailing guide to spir- 
itual truth, so Galen and other ancient writers were made 
the guides to scientific truth and thought. The baneful 
effects of this in stifling inquiry and in reducing knowledge 
