242 THE ZOOLOGIST. 



The reverse of the vernal picture, and the feelings awakened 

 by it, is found in the autumnal migration. The disappearance 

 of our faithful house and garden friends, the sudden silence of 

 wood and meadow, makes us sad, because it tells of evane- 

 scence, and heralds inclement weather, thus rendering our de- 

 pression doubly acute. The autumnal migration leaves its im- 

 pression on the mind of the people too, an impression sometimes 

 so powerful that a great nation cannot shake off the shackles 

 of regret. I need only refer to the German song of the 

 Swallow, written by Herlossohn, and set to music by the classical 

 composer Abt, familiar alike to cottage and palace, as a testi- 

 mony of this general harmony of feeling. I might perhaps 

 add some fresh tints, but my sense of duty forbids me to do so. 

 The fact that I have to speak in the heart of England, on the 

 occasion of a strictly scientific congress, is decisive. 



The direction the thought of England requires me to take on 

 this subject is an easy question to decide. England has given 

 the world three stars of the highest order. The first was Bacon 

 of Verulam, who advises us, in considering the phenomena of 

 Nature, to adopt the method of experience, a course which amounts 

 to the exclusion of speculation, and especially of fancy. The second 

 was Isaac Newton, who by the law of gravitation has taught us 

 the all-conquering power of the laws of nature, and has explained 

 the equilibrium of the universe, thus putting exact science in 

 the foreground. The third was Charles Darwin, who has con- 

 quered the rigidity of the conception of organisms, and has 

 explained the idea of evolution. The example of these three 

 great men must cause me, especially on English soil, to confine 

 myself to facts, to the exclusion of sophistry, fancy, and belief in 

 authority. 



Before, however, I undertake the development of this theme, 

 I must make the following remark. In spite of all Bacon, 

 Newton, and Darwin did, in spite of the victorious advance of 

 the exact and inductive branches of science, speculative theories 

 held the day, even during the nineteenth century, in the considera- 

 tion of the migration of birds, taken as a science. This is found 

 even to-day in the nature of the phenomenon itself. The power 

 of flight of birds, of nocturnal migration, and many other un- 

 known circumstances led people to talk of "riddles," even of 



