m^ 







rn 



o o o 



DD 



If 



o o o 



OTTO HERMAN. 



1. All that has been designated „mystery" or „riddle" in connection 

 with the Migration of Birds, is, in point of fact, only a want of inductive 

 and positive knowledge, and nothing but the neglect of a proper division 

 of labour in cases where the individual alone cannot attain the aim. 



2. The observation and its elaboration divides into three organi- 

 cally connected parts: 



I. the Migratory : progress of Migration ; 

 \\. the Phaenological : connection with Meteorology; 

 III. the Biological: causal impulse. 



3. Parallel to the oscillating movement of Migration — generally 

 from North to South and vice-versa — goes the sexual impulse and its 

 periodical development and retrogression, which, consequently, has an 

 essential influence on Migration. The attendance of sexually immature 

 individuals belongs to the physiology of masses. 



4. In consequence of the power of flight. Birds find their way, 

 without special organs, otherwise than animals fixed to the ground. 



5. The lower the altitude of the locality, the earlier the arrival. 



(2) 19 (Z) 



