GENERAL SUMMARY. 643 



such as that of which we are ourselves conscious in our own voluntary move- 

 ments, or which we trace in the operations of the more intelligent Vertebrata. 

 For, in the first place, these actions are invariably performed in the same man- 

 tier by all the individuals of a species, when the conditions are the same ; and 

 thus are obviously to be attributed rather to a uniform impulse, than to a free 

 choice ; the most remarkable examples of this being furnished by the economy 

 of Bees, Wasps, and other " social" Insects, in which every individual of the 

 community performs its appropriate part, with the exactitude and method of a 

 perfect machine. The very perfection of the adaptation, again, is often of it- 

 self a sufficient evidence of the unreasoning character of the beings which per- 

 form the work ; for, if we attribute it to their own intelligence, we must admit 

 that this intelligence frequently equals, if it does not surpass, that of the most 

 accomplished Human reasoner. 1 Moreover, these operations are performed 

 without any guidance from experience ; for it can be proved in many cases, that 

 it is impossible for the beings which execute them to have received any instruc- 

 tion from their parents ; and we see that they do not themselves make any pro- 

 gressive attempts towards perfection, but accomplish their work as well when 

 they first apply themselves to it, as after any number of repetitions of the same 

 acts. It is interesting to observe, moreover, that as these instinctive operations 

 vary at different periods of life; so is there a corresponding variation in 

 the structure of the Nervous system. Thus we see that, in the larva of the 

 Insect, these operations are entirely directed towards the acquisition of food ; 

 and its organs of sense and locomotive powers are only so far developed as to 

 serve this purpose. But in the imago or perfect Insect, the primary object is 

 the continuance of the race; and the sensorial and motor endowments are 

 adapted to enable the individual to seek its mate, and to make preparations (fre- 

 quently of a most elaborate kind) for the nurture of the offspring. Hence we 

 can scarcely fail to arrive at the conclusion, that the adaptiveness of the instinct- 

 ive operations of Insects, &c., lies in the original construction of their nervous 

 system, which causes particular movements to be executed in direct respondence 

 to certain impressions and sensations. And this view is confirmed by the com- 

 parison of these movements with those which have been always recognized as 

 u instinctive" in the Human being ; thus, the act of sucking in the infant re- 

 quires the combined exertion of a considerable number of muscles, which com- 

 bination is clearly not the result of intelligence and will, but is a purely " reflex" 



1 Of this we have a most remarkable example in the architecture of the common Hive- 

 Bee. The hexagonal form of the cell is the one in which the greatest strength, and the 

 nearest approach to the cylindrical cavity required for containing the larva, are attained, 

 with the least expenditure of material. But the instinct which directs the Bees in the 

 construction of the partition that forms the bottom or end of the cell, is of a nature still 

 more wonderful than that which governs its general shape. The bottom of each cell 

 rests upon three partitions of cells upon the opposite side of the comb ; so that it is ren- 

 dered much stronger, than if it merely separated the cavities of two cells opposed to one 

 another. The partition is not a single plane surface ; but is formed by the union of 

 three rhomboidal planes, uniting in the centre of each cell. The angles formed by the 

 sides of these rhombs were determined by the measurements of Miraldi to be 109 28' 

 and 70 32' ; and these have been shown, by mathematical calculation, to be precisely the 

 angles, at which the greatest strength and capacity can be attained, with the least expen- 

 diture of wax. The solution of the problem was first attempted by Koenig, a pupil of the 

 celebrated Bernouille ; and as his result proved to differ from the observed angle by only 

 two minutes of a degree, it was presumed that the discrepancy was due to an error of ob- 

 servation, which it was easy to account for by the smallness of the surfaces whose incli- 

 nation had to be measured. The question has been since taken up, however, by Lord 

 Brougham (Appendix to his Illustrated edition of "Paley's Natural Theology"); who 

 has worked it out afresh, and has shown that, when certain small quantities, neglected by 

 Koenig, are properly introduced into the calculation, the result is exactly accordant with 

 observation the Bees being thus proved to be right, and the Mathematician wrong. 



