INSTINCT. 



he has himself accurately described. The fol- 

 lowing appears a more comprehensive enume- 

 ration. Three great classes of instinctive ac- 

 tions may be distinguished ; the first designed 

 for the preservation of individuals ; the second 

 for the propagation and support of their off- 

 spring; and the third for various purposes im- 

 portant either to the race of animals exhibiting 

 them, or to other animals, but not distinctly 

 referable to either of the formei heads. 



Each of these classes admits of obvious sub- 

 divisions. 



I. Of instincts designed for the preservation 

 of the individuals exhibiting the>, we may 

 enumerate the following : 



1. All animals are endowed with instincts 

 prompting them to some means of escaping or 

 repelling injury or violence, but these are ex- 

 ceedingly various, both as to the kind and as 

 to the degree of complexity of the actions 

 which they excite; from the simple retraction 

 of the tentacula of the infusory Vorticella, or 

 of the Medusa, Polype, or Actinia, up to the 

 active and formidable resistance of the ele- 

 phant or the tiger. The most common instinct 

 of self-preservation excited by the emotion of 

 fear, is that which prompts to flight, an in- 

 stinct so obviously existing in the human 

 species, that the effort by which it is resisted 

 has in all ages been regarded with respect; and 

 another very common propensity in animals is 

 that which prompts to concealment. This is 

 often combined with flight, as in most of the 

 Carnivorous Mammalia, the Rodentia, the Ce- 

 tacea, the diving birds, reptiles, insects, &c. ; 

 but some of the higher animals, and many of 

 the Mollusca and insects, and others of the 

 lower tribes, remain quite motionless and 

 counterfeit death when under the influence of 

 fear ;* and it is remarkable that when the cir- 

 cumstances of the animals render this mode of 

 defence the most effectual, it is that adopted, 

 in preference to flight, even by single species 

 of families, the other members of which shew 

 no such instinct, as in the case of the ptarmi- 

 gan, which so frequently cowers among the 

 grey lichen, or the snow on the mountain- 

 tops, instead of taking wing like the moor fowl, 

 or in that of the hedge-hog, which on occasion 

 of any imminent danger makes no effort but 

 that of coiling itself into a ball. 



In many instances the instinct either of flight 

 or concealment is aided by very various special 

 contrivances, equally instinctive, fitted either 

 to deceive, or to alarm, or injure an assailant. 

 Some even of the Mollusca, and some of the 

 reptiles, as the toad, squirt water on him ; 

 many reptiles and some lower animals, as 

 the scorpion, bee, wasp, &c., even some of the 

 gelatinous radiata,f have the power of emit- 



* " In this situation, spiders will suffer them- 

 selves to be pierced with pins and torn to pieces, 

 without discovering the smallest sign of pain. 

 This simulation of death has been ascribed to a 

 strong convulsion or stupor occasioned by terror ; 

 but this solution of the phenomenon is erroneous. 

 If the object of terror is removed, in a few se- 

 conds the animal runs off with great rapidity." 

 Duncan on Instinct. 



t Kirby, vol. i. p. 198. 



ting irritating matter of greater or less inten- 

 sity ; the electrical animals, as the gymnotus 

 and torpedo, use their appointed weapons ; the 

 hedge-hog and porcupine oppose their sharp 

 thorns to any one who attempts to molest them; 

 many insects and some reptiles protect them- 

 selves by emitting peculiarly fetid effluvia; the 

 cuttle-fish tribe have the remarkable power of 

 emitting an inky fluid which darkens the wa- 

 ter and hides them ; and on the other hand 

 there is reason to believe that the phosphores- 

 cent light which so many marine animals ex- 

 hibit, may be suddenly augmented on occa- 

 sion of any threatening of injury, and serve as 

 a means of defence.* (See LUMINOUSNESS.) 

 The means of defence, and the instincts guid- 

 ing them, in the case, not only of the higher 

 Carnivorous animals, but many of the stronger 

 of the Herbivorous classes, the elephant, the 

 hog, the horse, the buffalo, the deer, &c. re- 

 quire no illustration. 



The instinct which prompts many animals to 

 utter cries when injured or threatened, (as well 

 as on other occasions and for other purposes,) 

 deserves notice as a means of protection, parti- 

 cularly on this account, that as it is one of the 

 instincts which most clearly extends to the 

 human race, so we may perceive in man, as 

 well as in some of the lower animals, that its 

 use is not merely to frighten assailants, but 

 especially to procure assistance and protection 

 for the young animal from its parents. 



2. The most conspicuous and most remark- 

 ably varied of the instincts under this head 

 are those by which the food of different ani- 

 mals is procured. With the exception of the 

 sponges, and some others of the lowest Zoo- 

 phyta, in which the nourishment is supplied by 

 currents, all animals have organs corresponding 

 to a mouth and stomach, into which aliments 

 are taken by a process of deglutition, imply- 

 ing sensations and instinctive efforts conse- 

 quent on these; and in the Articulata and 

 Mollusca, the most important central organ of 

 the nervous system seems to be the nervous 

 collar surrounding the oesophagus, which in 

 the vertebrated animals seems to be developed 

 and subdivided into the first, fifth, and part of 

 the eighth pairs of nerves, with the corres- 

 ponding portions of the cerebro-spinal axis, by 

 which the sensation of hunger is felt, the 

 suitable nourishment discriminated, and the 

 instinctive effort, whether of deglutition only, 

 or of mastication more or less powerful ac- 

 cording to the food, is excited. 



In some instances subsidiary instincts are 

 also implanted in certain animals, which are 

 essential to their digestion and nutrition. The 

 art of cookery, as universally practised by the 

 human race, may be said to be the result of 

 experience; but this cannot be said of the pro- 

 pensity of many animals to swallow salt, still 

 less of the swallowing of gravel or pebbles by 

 the graminivorous birds, or of the copious 

 draughts of water, sufficient to store the nu- 

 merous and peculiar cells of their first and 

 second stomachs, which are taken by the camel 



* Ibid, vol. i. p. 178. 



