4 LECTUKES ON BIOLOGY 



greatest advancement. The object of this lecture is not to give 

 a complete record but rather to present briefly the gradual rise 

 of the natural sciences, the first dawn of the evolution theory ; 

 afterwards, the rapid decay of science, and finally, its brilliant 

 development during the eighteenth century. 



If one looks back upon the history of natural sciences in the 

 Middle Ages and modern times, their rapid rise, in particular 

 that of the descriptive branches, above all of zoology and botany, 

 seems almost inconceivable. On one side we see the grossest 

 superstition, or, at the best, defective and inaccurate knowledge ; 

 on the other, an almost inexhaustible wealth of facts and accepted 

 principles. One may indeed regard with pride the results of 

 the untiring labour of the two preceding centuries. 



According to Ben Akiba there is nothing new under the sun. 

 Looking backwards from the ignorance and suspicion of the 

 Middle Ages, the loftiness of Greek civilization, evidenced by 

 the high state of their knowledge of nature, seems equally incom- 

 prehensible ; and it is still more difficult to understand that such 

 great wealth of knowledge as was stored in the mind of an 

 Aristotle should pass from the memory of man, almost without 

 leaving a trace behind. 



Anaximander, a contemporary, disciple, and countryman of 

 Thales, already taught the gradual natural evolution and change 

 of the Universe and the organisms. He perceives the original 

 principle in the 'Apeiron,' the Infinite. It has no origin and 

 no end, changing only its forms. He conceived that from this 

 unlimited original matter there proceeded by spontaneous division 

 the warm and the cold. From these was formed the moist, and 

 out of it, through drying, the earth, the air, and an all-surrounding 

 fireball which finally burst and gave rise to the sun and the 

 other heavenly bodies. The influence of the sunrays developed 

 out of the primordial mud the first degree of organic life, certain 

 vesicular formations which gradually developed into fish-like 

 animals. In proportion as the drying process went on, some 

 of the fishes left the moist element and under the influence of 

 changed external conditions and a new mode of life changed into 

 the various species of land animals. Finally the species man 

 naturally evolved from animal, ancestors. ' But whence all 

 beings have sprung thence they must return, as a penance for 



