ON INSTINCT. 



towards the reversed bottom of the vessel ; and that where the eyes had 

 been placed downwards, the young shoots had turned round so as to take 

 the same direction. As one experiment leads on to another, he deter- 

 mined to try the effect of placing other seeds of the same kinds in a tub, 

 to which a rotatory motion should be given, so that every part of it might be 

 equally and alternately uppermost, and the seeds should have no advantage 

 in one direction over another. Here, as we often behold in other cases, 

 the instinctive principle of accommodation was baffled by a superior 

 power, and the different shoots, instead of ever turning round, uniformly 

 adhered to a straight line, except where they met with a pebble or any 

 other resistance, when they made a curve to avoid such obstruction, and 

 then resumed a straight line in the direction into which they were thereby 

 thrown, without ever endeavouring to return to the original path. 



Among animals we have various proofs of a like impulse, and we have 

 also proofs of its being occasionally overpowered by a stronger cause. 

 Thus, in cases of eruptive fever, there is an obvious effort of the instinct- 

 ive principle to tlirow the morbific matter towards the surface of the 

 body, where it can do least mischief And where a deep-seated abscess 

 has formed in the immediate neighbourhood of a cavity that cannot be 

 opened into without great danger, as that of the chest or the stomach, 

 the same instinctive princrple of preservation leads forward the action m a 

 different direction, though, as in the experiment of the bean-seeds in the 

 inverted tub, with much greater labour and difficulty ; and the abscess at 

 length opens externally ; and the remedial process of the formation of 

 new living matter v/hich immediately succeeds, commences under the 

 same mysterious guidance. If, in the course of this common tendency to 

 the surface, an obstructive cause be encountered, of superior force to the 

 instinctive principle itself, the latter, as in the experiment of the beans 

 exposed to the action of a rotatory motion, is overpowered, and the result 

 is doubtful, and often fatal. 



But these examples are general : let us advert to a few of a more par- 

 ticular nature. All the different species of birds, in constructing their 

 nests, not only adhere to a pecuhar plan, but, wherever they can obtain 

 them, to peculiar kinds of materials ; but if these materials be not to be 

 procured, the accommodating power of the instinctive principle, as in the 

 cases just related, directs them to others and suggests the best substitutes. 

 Thus the red-breast uniformly prefers oak leaves as a lining for her nest, 

 wherever she can acquire them ; but if these be not to be had, she sup- 

 plies the want by moss and hair. So where the bird is of small size, and 

 the eggs are naturally numerous, the nest is always made proportionably 

 warm, that the nestlings may all equally partake of the -vivifying heat. 

 Thus the wren, who lays from ten to eighteen eggs, constructs her little 

 edifice with the greatest care and of the warmest materials ; while the 

 plover and the eagle, whose eggs are so few that the body may easily cover 

 them, build with little solicitude, and sometimes content themselves with 

 the naked cleft of a rock. And thus too, in very cold winters in Lapland, 

 the fond waterfowl will occasionally strip the down off its breast to line its 

 nest and protect its progeny. 



When a wasp, in attempting to transport a dead companion from the 

 uest, finds the load too heavy, he cuts of its head, and carries it out \xi 

 two portions.* 



* SmelUej vol. ii. 161. Beaumur, torn, xl 24L For an account of other curious isstances 



