re = ™ a a | Ae ll OY Re, 
4 AN OUTLINE OF THE THEORY. 
connected with a history of this hypothesis, its roots are 
found far back in the early ages of Greek philosophy. A 
theory of evolutionary development was first propounded 
by Greek thinkers living about 600 years B. C. The hu- 
man mind is ever on the search for unifying principles, 
principles which account for entire groups of natural 
phenomena, and not for isolated phenomena only. The 
Greek mind sought a principle by which to account for 
the manifold and diverse forms of life in nature. 
Whence do all things;come? How have they come to be 
what they are? Questions about the nature of the uni- 
verse in which we live have been asked from the very 
beginning. The moment the human mind began to re- 
flect the notion that the vegetation which covers the earth, 
the animals which inhabit it, the rocks and hills, the 
mountains and valleys which constitute its physical fea- 
tures, may have undergone changes in past time, and that 
all the phenomena which constitute the animal, vegetable 
and mineral worlds as they now exist, are but modifica- 
tions of other forms which have had their day and their 
philosophy, the idea of development became prominent. 
The early Greek philosophers were the first to attempt 
answers to these problems. Many of them held that all 
things natural sprang from what they called the original 
elements—fire, air, earth, water. Anaximander held that 
animals were begotten from the earth by means of heat 
and moisture; and that man was developed from other 
beings different in form. Empedocles had a fantastic 
theory, viz., that the various parts of man and animals 
at first existed independently, and that these—for instance, 
arms, legs, feet, eyes, etc., gradually combined—perhaps 
after the manner in which automobiles are assembled ; 
and that these combinations became capable of existing 
and even of propagating and reproducing themselves. — 
Anaxagoras was of opinion that animals and plants 
