350 SPECIAL INBTINGT8. 



tication, for the mother hen has almost lost by disuse the 

 power of flight. 



Hence, we may conclude that under domestication in- 

 stincts have been acquired and natural instincts have been 

 lost, partly by habit and partly by man selecting and 

 accumulating, during successive generations, peculiar 

 mental habits and actions, which at first appeared from 

 ■what we must in our ignorance call an accident. In some 

 cases compulsory habit alone has sufficed to produce in- 

 herited mental changes. ^ In other cases compulsory habit 

 has done nothing, and all has been the result of 

 selection, pursued both methodically and unconsciously; 

 but in most cases habit and selection have probably 

 concurred. 



SPECIAL INSTINCTS. 



We shall, perhaps, best understand how instincts in a 

 state of nature have become modified by selection by con- 

 sidering a few cases. I will select only three, namely, the 

 instinct which leads the cuckoo to lay her eggs in other 

 birds' nests; the slave-making instinct of certain ants, and 

 the cell-making power of the hive-bee. These two latter 

 instincts have generally and justly been ranked by natural- 

 ists as the most wonderful of all known instincts. 



INSTINCTS OF THE CUCKOO. 



It is supposed by some naturalists that the more imme- 

 diate cause of the instinct of the cuckoo is that she lays 

 her eggs, not daily, but at intervals of two or three days, 

 so that if she were to make her own nest and sit on her 

 own eggs, those first laid would have to be left for some 

 time uniucubated or there would be eggs and young birds 

 of different ages in the same nest. If this were the case 

 the process of laying and hatching might be inconveni- 

 ently long, more especially as she migrates at a very 

 early period, and the first hatched young would probably 

 have to be fed by the male alone. But the American 

 cuckoo is in this predicament, for she makes her own nest 

 and has eggs and young successively hatched, iiU at the 

 same time. It has been both asserted and denied that 



