INSTINCTS. 175 



nests nearly in the same manner as in the wild state, and 

 sit upon their eggs. This is sufficient to prove an instinct, 

 without having recourse to experiments upon birds, hatched 

 by artificial heat, and deprived, from their birth, of all 

 communication with their species ; for we can hardly bring 

 ourselves to believe, that the parent bird informed her un- 

 fledged pupil of the history of her gestation, her timely 

 preparation of a nest, her exclusion of the eggs,- her long 

 incubation, and of the joyful eruption at last of her expect- 

 ed offspring , all which the bird in the cage must have 

 iearnt in her infancy, if we resolve her conduct into institu- 

 tion. 



Unless we will rather suppose that she remembers her 

 own escape from the egg ; had attentively observed the 

 conformation of the nest in which she was nurtured; and 

 had treasured up her remarks for future imitation. Which 

 is not only extremely improbable, (for who that sees a 

 brood of callow birds in their nest, can believe that they 

 are taking a plan of their habitation ?) but leaves unac- 

 counted for, one principal part of the difficulty, " the pre- 

 paration of the nest before the laying of the egg.^^ This 

 she could not gain from observation in her infancy. 



It is remarkable also, that the hen sits upon eggs which 

 she has laid without any communication with the male ; 

 and which are therefore necessarily unfruitful. That se- 

 cret she is not let into. Yet, if incubation had been a sub- 

 ject of instruction or of tradition, it should seem that this 

 distinction would have formed part of the lesson ; whereas 

 the instinct of nature is calculated for a state of nature; 

 the exception, here alluded to, taking place, chiefly, if not 

 solely, amongst domesticated fowls, in which nature is 

 forced out of her course. 



There is another case of oviparous economy, which is 

 still less likely to be the eflect of education, than it is even 

 in birds, namely, that of moths and butterjlies, which de- 

 posit their eggs in the precise substance, that of a cabbage 

 for example, from which, not the butterfly herself, but the 

 caterpillar which is to issue from her egg, draws its ap- 

 propriate food. The butterfly cannot taste the cabbage. 

 Cabbage is no food for her ; yet in the cabbage, not by 

 chance, but studiously and electively, she lays her eggs. 

 There are, amongst many other kinds, the willow cater- 

 pillar, and the cabbage caterpillar; but we never find upon 

 a willow, the caterpillar which eats the cabbage ; nor the re- 

 verse. This choice, as appears to me, cannot in the butter- 



