INSTINCT OF INSECTS. 849 
the form of their cells when cireumstances require it, and that in a way 
which one would not have expected. 
Having placed in front of a comb which the bees were constructing 2 
slip of glass, they seemed immediately aware that it would be very difficuit 
to attach it to so slippery a surface ; and instead of continuing the comb in 
a straight line, they bend it at a right angle, so as to extend beyond the slip 
of glass, and ultimately fixed it to an adjoining part of the wood-work of 
the hive which the glass did not cover. This deviation, if the comb had 
been a mere simple and uniform mass of wax, would have evinced no small 
ingenuity; but you will bear in mind that a comb consists on each side, or 
face, of cells having between them bottoms in common; and if you take a 
comb, and, having softened the wax by heat, endeavour to bend it in any 
part at a right angle, you will then comprehend the difficulties which our 
little architects had to encounter. The resources of their instinct, how- 
ever, were adequate to the emergency. They made the cells on the convex 
side of the bent part of the comb much /arger, and those on the concave 
side much smaller than usual; the former having three or four times the 
diameter of the latter: But this was not all. As the bottoms of the small 
and large cells were as usual common to both, the cells were not regular 
prisms, but the small ones considerably wider at the bottom than at the top, 
and conversely in the large ones! What conception can we form of so 
wonderful a flexibility of instinct? How, as Huber asks, can we com- 
prehend the mode in which such a crowd of labourers, occupied at the 
same time on the edge of the comb, could agree to give to it the same 
curvature from one extremity to the other; or how they could arrange 
together to construct on one face cells so small, while on the other they 
imparted to them such enlarged dimensions? And how can we feel 
adequate astonishment that they should have the art of making cells of 
such different sizes correspond ?* 
After this long but I flatter myself not wholly uninteresting enumeration, 
you will scarcely hesitate to admit that insects, and of these the bee pre- 
eminently, are endowed with a much more exquisite and flexible instinct 
than the larger animals. But you may be here led to ask, Can all this be 
referred to instinct ? Is not this pliability to circumstances —this surprising 
adaptation of means for accomplishing an end—rather the result of 
reason? 
You will not doubt my allowing the appositeness of this question, when 
I frankly tell you that so strikingly do many of the preceding facts seem at 
first view the effect of reason, that in my original Nera of the letter you 
are now reading, I had arranged them as instances of this faculty. But 
mature consideration has convinced me (though I confess the subject has 
great difficulties) that this view was fallacious; and that though some 
circumstances connected with these facts may, as I shall hereafter show, be 
referable to reason, the facts themselves can only be consistently explained 
byregarding them as I have here done, as examples of variations of particular 
Instincts :—and this on two accounts. 
In the first place, these variations, however singular, are dimifed in their 
extent: all bees are, and have always been, able to avail themselves of a 
certain number, but not to increase that number. Bees cemented their 
1 Huber, ii, 219. 
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