244 THE ZOOLOGIST. 



mankind, had to protest against this, as he did in 1824 ; yet 

 the misbelief has nevertheless prevailed in more or less obscure 

 writings until the present day. 



Even in the high-class works of famous authors of our own 

 time echoes of this mediaeval belief in miracles are still discernible : 

 mention is made of the gift of presentiment, of miraculousness, 

 of puzzles which, if reduced to Bacon's terminology, are nothing 

 but "want of inductive knowledge, and of positive notion result- 

 ing therefrom." 



It would require the foresight and patience of a Theseus to 

 unravel the labyrinth of peasants' maxims dealing with the 

 world of birds and the foretelling of the weather. 



Taken as a whole, the science did not get much farther than 

 an amassing of arrival- and departure-data, which finally formed 

 a chaos that daunted and still daunts the boldest authors. Most 

 of them preferred to take the thing at the easy end : to draw 

 far-going conclusions from a few data, to exert their ingenuity, 

 sometimes only their fancy. This state of things naturally 

 resulted in many singular contradictions, of which I would like, 

 with your kind permission, to mention a few : — 



Naumann. — There are definite routes of migration. 

 Homey er. — There are no routes of migration. 



Weismann. — The birds learn how to migrate. 

 Gaetke. — The birds act by instinct. 



Palmen. — Orientation is a traditional gift. 

 Weismann. — Orientation is congenital. 



Gaetke. — There is no leadership. 

 Weismann. — There is leadership. 



Wallace. — The weather has no essential influence. 

 Homeyer. — The weather has an essential influence. 



Naumann. — Temperature plays a very important part. 

 Angot. — Temperature is not an incentive. 



Lucanus. — The flight takes place at a height of 3000 ft. 

 Gaetke. — The flight goes on at a height sometimes of 35,000 ft. 



Braun. — The original home of the birds is the tropics. 

 Deichler. — The original home is not the tropics, &c. 



