$26 ON THE DISTINCTIVE CHARACTERS OF 



intrusting her eggs to the parent heat of the sun. The egg in each separate 

 cell or aperture is soon hatched, and finds its food duly prepared for it, and 

 from its enfeebled state incapable of resisting its attack, though preserved 

 from putrefaction by the little life that has remained to it. It feeds pro- 

 gressively on the twelve caterpillars ; and by the time it has exhausted them, 

 becomes fitted for, and converted into, a chrysalis ; in due time it awakes from 

 its dormancy, works its way to the surface of the earth, throws off its chry- 

 salid investment, finds itself accommodated with wings, rises into the atmos- 

 phere, feeds on the honey of plants instead of on maggots; and at length 

 pursues the very same train of actions to provide itself with a progeny which 

 was pursued by the parent insect of the year before. 



In what I have thus far advanced, I have chiefly proved, however, that 

 instinct may exist separately : I will next proceed to a few examples, in which 

 it will be clear to every one that it may exist in conjunction witli each of the 

 other two principles of sensation and intelligence. 



And, first, as to its union with sensation. Wherever a nervous system is 

 to be traced, which alone is the source of sensation, we have abundant proofs 

 of such an alliance. We meet with it, without having language by which to 

 describe it, in the glow and elasticity of health, in the satisfaction of a cheer- 

 ful meal, and in the refreshment of sound and natural sleep after fatigue ; and 

 we meet with it still more obviously, and in diversities which language is ca- 

 pable of characterizing, in all those natural emotions to which we have just 

 adverted, and which, in consequence of such alliance, have obtained the 

 popular name of instinctive sensations or feelings, but which in reality are 

 peculiar instincts combined with peculiar feelings. 



Let us select a few other examples. We are told by Galen,* that on opening 

 a goat big with young he found one of the young ones alive, which he hastily 

 snatched up, and took into a room where there were various vessels severally 

 fitted for the purpose with wine, oil, honey, milk, grains, and fruits. The 

 little kid first rose upon its feet and walked ; then shook itself, and scratched 

 its side with one of its hoofs; it next smelt alternately at all the dishes before 

 it, and at last fixed upon and licked up the milk. In this case the sense of 

 smell went distinctly in aid of the instinctive search after food, and deter- 

 mined the particular kind : so that the instinct and the sensation co-operated. 

 Thus rabbits, when left to the operation of pure instinct, dig holes in the 

 ground for warmth and protection : but after continuing for some time in a 

 domestic state, and finding that they can obtain a more comfortable asylum 

 by other means, and with less labour, they seldom pursue, even when they 

 have an opportunity, the -instinctive process, but burrow in the straw, or 

 whatever material is provided for them. 



In this case the sense of superior comfort combines itself, as in the pre- 

 ceding, with the instinct, and pursues the same end, though by a change of 

 the means. So again, the new-born young of all animals, in whatever way 

 they take their food, are at first stimulated by instinct alone. The lamb 

 sucks, the chicken pecks, and the nestling of the sparrow gapes. In like 

 manner, the mother secretes or selects its food from an instinctive stimulus 

 alone. The udder of the dam swells and becomes painful, the crop of the 

 pigeon does the same ; and there are some birds, whose common food is grain, 

 that during this season devour for their young, spiders and other insects, 

 which nothing could induce them to touch at any other .time. This sweet 

 intercourse of natural action lays a foundation for something that in a short 

 time shows itself to be superior to instinct, though it has often, but erroneously, 

 been so denominated. The young of two different mothers, if interchanged 

 as soon as they are born or hatched, are as satisfied with the foster or suppo- 

 sititious as with the natural parent : and the mothers, unless made suspicious 

 of the deception, are as satisfied with their foster or supposititious young. 

 But let the same interchange be attempted a week or a month afterward, and 

 in no case will it succeed. . Short as has been the intervening period, there 



* De Locis, lib. vl. cap. 8. 



