ON INSTINCT. 210 



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 some- 

 times content themselves with the naked cleft of a rock. And thus, too, in 

 very cold winters in Lapland, the fond water-fowl 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 nest, 

 finds the load too heavy, he cuts off its head, and carries it out in two portions.* 



A strawberry offset planted in a patch of sand will send forth almost th^ 

 whole of its runners in the direction in which the proper soil lies nearest, and 

 few, and sometimes none, in the line in which it lies most remote. 



When a tree which requires much moisture (says Mr. Knight) has sprung 

 up or been planted in a dry soil, in the vicinity of water, it has been observed 

 that a much larger portion of its roots has been directed towards the water ; 

 and that when a tree of a different species, and which requires a dry soil, has 

 been placed in a similar situation, it has appeared, in the direction given to 

 its roots, to have avoided the water and moist soil."t 



" When a tree (remarks Dr. Smith) happens to grow from seed on a wall 

 (and he particularly alludes to an ash in which the fact actually occurred), it 

 has been observed, on arriving at a certain size, to stop for a while and send 

 down a root to the ground. As soon as this root was established in the soil, 

 the tree continued increasing to a large magnitude."! 



The best means, perhaps, that a plant can possess of resisting the effects 

 of drought, is a tuberous or bulbous root. The grass called phleum pratense, 

 or common catstail, when growing in pastures that are uniformly moist, has 

 a fibrous root, for it is locally supplied with a sufficiency of water; but in 

 dry situations, or such as are only occasionally wet, its root acquires a bul- 

 bous form, and thus instinctively accommodates the plant with a natural 

 reservoir. 



And there are various other grasses, as the alopecurus geniculatus, or geni- 

 culate foxtail, that exhibit the same curious adaptation.^ 



There are some philosophers and physiologists who have endeavoured to 

 ascribe the whole of these very extraordinary phenomena to the mechanical 

 powers of gravitation and centrifugal force: among whom I may especially 

 mention Mr. Knight, who has attempted it in a very ingenious paper to 

 which I have just alluded. There are others who ascribe them to the opera- 

 tion of an intelligent principle, among whom, more especially, as I have 

 already observed, is Dr. Darwin. Of these two causes the instances just sub- 

 mitted to you, and thousands more might be added to them, sufficiently 

 prove that the first is inadequate and that the second does not always exist ; 

 at least that the phenomena are often found in organized forms in which, to 

 a certainty, the precise organs do not exist which are the only known seats 

 of intelligence and sensation in the visible world. They are hence to be 

 resolved into another cause, equally remote from either, more complex in its 

 operations than that of gravity, but less so, perhaps, than those of intelligence 

 and feeling ; embracing a distinct family of well-defined and cognate actions, 

 always aiming at the same common end, the perfection, preservation, or 

 reproduction of the system in which they exist; and constituting what we 

 should denominate instinct, the general property of the living principle or the 

 law of organized life in a state of action. 



But the subject is too important to be closed liere. It remains yet to point 

 out the difference between instinct and sensation or feeling, as well as be- 

 tween instinct and reason. It remains yet for me to show you that all these 

 are equally distinct principles; that they may exist separately or conjointly; 



♦Smellie, vol. ii. 151. Reaumur, torn. xi. 241. For an account of otlier curious instances of instincts, fn 

 insects, see the Swedish Amtenitaies Acadennica), vol. ill. ai t. 45. Noxa Inseciorum, by M. A. Boechner 

 1752; and compare with these the younger Hiiber's Recherches sur les Mosurs des Fourmia Indigenea 



t Phil. Trans. 1811, p. 210. J Introd. to Botany, p. 114 



^ See SmiUi, Introd. to Bot. p. 113, and p. 41. 



