I04 Darivin and Roiuanes dealt with. 



" occasional habits," out of which Mr. Darwin — to 

 us rather illogically, and surely inadvertently — says 

 that instincts are developed with co-operation — be it 

 noted — of time and chance. Are these " occasional 

 habits " instincts, or what are they ? If they are got 

 purely out of occasional habits ; then certainly your 

 effect is greater than your cause, and so far outside it. 

 And at what point, pray, does the " occasional habit " 

 become an instinct ? 



XII. 



There is no such absolute uniformity in the case of 

 other birds, as against the cuckoo, in hatching eggs 

 simultaneously, as Mr. Darwin founds on here. In- 

 deed, there is no such thing as absolutely simul- 

 taneous hatching of eggs. It would be very trying 

 and troublesome to the female bird, if it were so : for 

 she has a duty to the shell — to clear It away ; and a 

 duty to the young bird — to dry and clean it. And, 

 transparently, it would be disadvantageous, if, while 

 she dried and cleaned one — three, four, five, six, or 

 even seven others were lying wet and cold, waiting 

 her attentions. I say then, firstly, and from observa- 

 tions alike of tame birds — canaries, linnets, and others 

 bred by me — and of wild birds, that, to a greater or 

 lesser degree, birds of different ages are invariably in 

 the same nest, and the first hatched young are in the 

 multitude of cases fed by the male alone, or by the 

 female receiving the food from the male and really 

 giving it to the young without leaving the nest — 

 the wonderful accommodation of the digestive organs 

 during incubation enabling her to do this for long, 



