APPENDIX. 357 



problem have often been confused together under the word 

 instinct.* With respect to the period of starting, it cannot 

 of course be memory in the young cuckoos' start ibr the first 

 time two months after their parents have departed : yet it 

 deserves notice that animals somehow acquire a surprisingly 

 accurate idea of time. A. d'Orbigny shows that a lame 

 hawk in S. America knew the period of three weeks, and 

 used at this interval to visit monasteries when food was dis- 

 tributed to the poor. Dihicult though it may be to conceive 

 how animals either intelligently or instinctively come to 

 know a given period, yet we shall immediately see that in 

 some cases our domestic animals have acquired an annual 

 recurring impulse to travel, extremely like, if not identical 

 with, a true migratory instinct, and which can hardly be due 

 to mere memory. 



It is a true instinct which leads the Brent Goose to try to 

 escape northwards ; but how the bird distinguishes north an( I 

 south we know not. ]^or do we know how a bird whicii 

 starts in the night, as many do, to traverse the ocean, keeps 

 its course as if provided with a compass. But we should be 

 very cautious in attributing to migratory animals any 

 capacity in this respect which we do not ourselves possess ;t 

 though certainly in them carried to a wonderful perfection. 

 To give one instance, the experienced navigator WrangelJ 

 expatiates with astonishment on the " unemng instinct " of 

 the natives of IST. Siberia, by which they guided him through 

 an intricate labyrinth of hummocks of ice with incessant 

 changes of direction ; while Wrangel " was watching the 

 different turns compass in hand and trymg to reason the- 

 true route, the native had always a perfect knowledge of it 

 instinctively." Moreover, the power in migratory animals of 

 keeping their course is not unerring, as may be inferred from 



* See E. P. Thompson on the Passions of Animals, 1851, p. 9; and 

 Ahson's remarks on this head in the Ct/clopcedia of Anatomy and Physiology, 

 article " Instinct," p. 23. 



t [I cannot refrain from drawing attention to the superiority of scientific 

 metliod and philosophical caution here displayed as contrasted with Professor 

 Hackel's views on the same subject, which in presence of this difficulty at once 

 conclude in favour of some mysterious additional sense (see p. 95). — G-. J. R.] 



X WrangeVs Travels, Eng. trans., p. 146. See also Sir Gr. Grey's Expe- 

 dition to Australia, vol. ii, p. 72, for interesting account of the powers of 

 the Australians in this same respect. The old French missionaries used to 

 believe that the N. American Indians were actually guided by instinct in 

 finding their way. 



