230 



ON INSTINCT. 



accomplishment of its object, isijoncealed from the view, it still exists ; and 

 ^ he endeavours to follow it up and develope it ;^ in which, however, it is 

 not worth while to accompany him, for the whole process, even upon his 

 own showing, is so complex, that it would rather require the genius of an 

 adult Newton to unfold it, than yield to the dawning powers of a new-born 

 infant. 



I will just observe, that in various cases of the instinctive faculty the 

 most excursive theorist cannot picture to his imagination any thing like a 

 chain of .thought, or previous reasoning ; any thing like a habit or imita- 

 tion, by which the means and the end are joined together. Let us take, 

 as an example, the very common instance of a brood of young ducks 

 brought up under a hen, and contrary to all the instincts and feelings of 

 the foster-mother, plunging suddenly into the water, while she herself 

 trembles piteously on the brink of the pond, not daring to pursue them, 

 and expecting every moment to see them drowned. By what kind of ex- 

 perience or observation, by what train of thought or reasoning has the 

 scarcely fledged brood been able to discern that a web-foot fits them for 

 swimming, and that a fissured foot would render them incapable ? — a 

 knowledge that mankind have only acquired by long and repeated contem- 

 plation, and which has never been fully explained to this hour. Habit, 

 imitation, and instruction, would all concur in teaching them, to flee from 

 the water, as a source of inevitable destruction : and yet in opposition to^ 

 all these influences and premonitions, we see them rush into it, and harm- 

 lessly : we see them obeying an irresistible impulse, which directs them to 

 what is fitting, stamped in the interior of their little frames, and which is 

 equally remote from the laws of mind and of mechanism. 



In like manner, by what process of imitation, education, or reasoning, 

 does the nut-weevil (curculio nucum) seek out exclusively, and with the 

 nicest knowledge of the plant, the green hazel in the month of August, 

 while its nut-shell is yet soft and easily penetrable ? What past experience 

 or course of argument instructs her that this is the fruit best adapted or 

 perhaps only adapted, to the digestive powers of her future progeny ? With 

 a finished knowledge of her art, as soon as she is prepared to depositeher 

 eggs, she singles out a nut, pierces it with her proboscis, and then, turning 

 round accurately, drops an egg into the minute perforation ; having ac- 

 complished which, she passes on, pierces another n«ut, drops another egg, 

 and so continues till she has exhausted her entire stock. The nut, not 

 essentially injured, continues to grow. The egg is soon hatched ; the 

 young larve or maggot finds its food already ripened and in waiting for it ; 

 and about the time of its full growth, fails with the mature nut to the 

 ground, and at length creeps out by gnawing a circular hole in the side. It 

 then burrows under the surface of the ground where it ^continues dormant 

 for eight months, at the termination of which time it casts its skin, com- 

 mences a chrysalis of the general shape and appearance of#the beetle kind, 

 and in the beginning of August throws oiF the chrysalid investment, creeps 

 to the surface of the ground, finds itself accommodated with wings, be- 



* " By a due attention to these circunastances, many of the actions, which at first sight 

 seemed only referable io an inexplicable instinct, will appear to have been acquired, like all 

 other animal actions that are attended with consciousness, by the repeated efforts of our 

 muscles under the conduct of our sensations or desires ;" — Zoonom. Lect. xvi. 2. 4. " If 

 it should be asked, what induces a bird to sit weeks on its first eggs, unconscious that a brood 

 of young ones will be the product ? the answer must be, that it is the same passion that in- 

 duces the human mother to hold her offspring whole nights and days in her fond armf , and 

 press it to her bosom, unconscious of its future growth to sense and manhood, till observation 

 or tradition have informed her."— Darwin. Sect, xyi, 13. 4. 



