1897- THE PROBLEM OF INSTINCT. 167 



been compared. Either then, these myriads of birds passed south- 

 ward to Holland or flew out to sea and were mostly lost. As Herr 

 Gatke does not mention any corresponding flights along the coasts of 

 Holland and Belgium it is to be presumed that they have not been 

 noticed, and we are almost forced to the conclusion that the greater 

 part of these young birds, whose immense numbers at Heligoland 

 excite so much astonishment, are really failures, and form a portion of 

 those which are annually eliminated by the severe test of migration ; 

 and if this be so, much of the marvel supposed to attach to the 

 successful migration of young birds disappears, since such " successful 

 migration," except in the case of a small percentage, does not occur. 

 There is one alleged instinct of great popular interest which 

 Mr. Lloyd Morgan does not deal with — the means by which many of 

 our domestic animals, especially cats, dogs, and horses, find their way 

 home under circumstances which seem to preclude any direct guidance 

 by the senses. Narratives of the most marvellous character have 

 been published, but, unfortunately, no systematic experiments appear 

 to have been made, except a few by the late Mr. Romanes. These 

 showed that a dog could exactly track its master's footsteps by scent, 

 and it was shown that the scent was derived from his shoes, which 

 must of course be full of perspiration and other emanations from the 

 skin, because when he wore new shoes or those of another person his 

 track could not be followed. In Nature, vol. vii., there is a con- 

 siderable discussion of this subject, and many remarkable cases are 

 narrated by various correspondents, but in none are all the data 

 given for arriving at a rational conclusion on the question. I then 

 wrote summarizing the discussion (Nature, vol. viii., p. 65), and 

 suggested a series of experiments, which would alone give us any real 

 information. My suggestion was that a dog whose antecedents were 

 known should be taken by a circuitous route by rail and road to some 

 spot where he had never been before, and should be there handed to 

 some person he did not know, who should carry him a short distance, 

 and on releasing him should keep him in sight, either on foot or 

 horseback, till the animal returned home, noting carefully every 

 movement and action. A moderate number of such experiments 

 would settle the question of instinct or sense-observation, and it is to 

 be hoped, now that a more intelligent interest is taken in the subject, 

 such experiments will be made. I may add that, theoretically, any 

 instinct of direction is almost inconceivable, because quadrupeds in a 

 state of nature do not require such an instinct. They learn, step by 

 step, the surroundings of their birth-place, extending their range, 

 perhaps, year by year, but never requiring to go back over a country 

 they have not previously traversed. In their case ordinary memory, 

 assisted by very acute senses, would be all they would need. In the 

 ■case of domestic animals returning home, we find that the recorded 

 time elapsed varies from a few hours to several days or weeks, even 

 when the distance can be easily traversed in a day. This shows that 



