LECTURES ON BIOLOGY 



new life with Darwin and, cleansed of all dross of mysticism, 

 opened to research undreamt-of paths. 



The zenith of natural philosophy in classic time is reached 

 with the age of Aristotle. Posterity has justly bestowed upon 

 this great man the name of Father of Natural Sciences. In him 

 we do not only find embodied the sum-total of the knowledge 

 of his time, but there are also numerous branches of knowledge 

 which he vastly enriched. It was he who first attempted a 

 classification of the animal kingdom according to the degree of 

 relationship. The boldness of this undertaking will be better 

 understood when we call to mind the fact that Aristotle knew 

 only some 500 different species, whilst we know to-day between 

 300,000 to 400,000. Yet so clearly saw this master-mind in spite 

 of this difficulty that the Aristotelian division has in its main 

 points been retained up to the present day. 



Aristotle was aided by a surprising store of detailed informa- 

 tion, much of which was re-discovered during the last century 

 by the great naturalist of Berlin, Johannes Miiller. Thus 

 Aristotle knew, to mention only two instances, that many sharks 

 are viviparous, and that whales and dolphins are not fishes but 

 animals. That such a mind should ponder on the origin of 

 the organic world and endeavour to find a natural explanation 

 cannot therefore excite surprise. 



With the death of the great Stagirite natural sciences rapidly 

 decay ; instead of scientific research we find the grossest super- 

 stition. Even Pliny the Elder who perished during an erup- 

 tion of Vesuvius A.D. 79 whilst commanding the Roman fleet at 

 Misenum is at the best only a very untrustworthy compiler. 

 If of anyone, it may be said of him that 



Viele Dinge wusste er freilich, 

 Doch alle wusste er schlecht. 



Pliny piled up whatever he found, without troubling himself 

 about the scientific value of his ' finds.' There is nothing of the 

 Aristotelian mind in him, and his division of the natural world 

 into ' land, water and air animals ' is no more scientific than 

 if he had divided it, as Weismann tersely remarks, according 

 to the alphabet. 



The decay of sciences proceeded apace, first under the Roman 



