ARCHITECTURE. 201 
insects to those of an uniform lateral pressure, under 
which cylinders of any soft substance take an hexa- 
gonal form. This comparison, however, is fanciful, 
and is not quite supported by facts. For some wasps 
make their combs—very small ones it is true—entirely 
of cylindrical cells, the lateral pressure notwithstand- 
ing. The other theory refers the form of the cells to 
a subjective influence, an instinctive impulse; and to 
this I must express my adhesion. It is not a fatal 
objection to this theory that wasps, where they are 
free to build in any form, as, for instance, at the edges 
of the comb, build cells of less regular shapes; for 
_ the hexagonal principle may still be traced in these 
irregular cells, though the result be obscured some- 
what by the stronger impulse, if I may be allowed to 
say so, of not taking unnecessary trouble where 
nothing is to be gained by such scrupulous accuracy. 
So far, indeed, from these irregularly hexagonal cells 
disproving the instinct theory, their occurrence is 
rather an argument for its correctness. For we can- 
not explain why such cells should take an hexagonal 
form at all, however rudely expressed, except on the 
assumption that they are built under an instinctive 
impulse.* 
Each building pellet is applied with great exactness 
to three sides, two of one cell, and one of an adjoin- 
ing cell. In this way the cell-walls are interlaced 
with one another; and much greater strength is 
given to the whole comb than if the three outer sides 
of each cell were built up independently of the three 
* This subject is discussed by Mr. Wood, and illustrated in his usual 
happy manner, both as regards bees and wasps, in ‘Homes without 
Hands,’ pp. 432 and 570. 
