38 THE HISTORY OF SCIENCE 



solstice the polar night must last for twenty-four 

 hours, and that the moon plays a part in the produc- 

 tion of the tides. Nevertheless, the whole book is 

 permeated by the idea that the purpose of nature is 

 to minister to the needs of man. 



It further marks the practical spirit among the 

 Romans that a work on agriculture by a Carthagin- 

 ian (Mago) was translated by order of the Senate. 

 Cato (234-149 B.C.), so characteristically Roman 

 in his genius, wrote (JDe, lie Rustled) concerning 

 grains and the cultivation of fruits. Columella wrote 

 treatises on agriculture and forestry. Among the 

 technical writings of Varro besides the book on agri- 

 culture, which is extant, are numbered works on 

 law, mensuration, and naval tactics. 



It was but natural that at the time of the Roman 

 Empire there should be great advances in medical 

 science. A Roman's interest in a science was keen 

 when it could be proved to have immediate bearing 

 on practical life. The greatest physician of the time, 

 however, was a Greek. Qalen (131-201 A.D.), who 

 counted himself a disciple of Hippocrates, began to 

 practice at Rome at the age of thirty-three. He was 

 the only experimental physiologist before the time 

 of Harvey. He studied the vocal apparatus in the 

 larynx, and understood the contraction and relax- 

 ation of the muscles, and, to a considerable extent, 

 the motion of the blood through the heart, lungs, and 

 other parts of the body. He was a vivisector, made 

 sections of the brain in order to determine the func- 

 tions of its parts, and severed the gustatory, optic, 

 and auditory nerves with a similar end in view. His 

 dissections were confined to the lower animals. Yet 



