542 THE FORMS OF TISSUES [ch. 



to their opposite neighbours ; and how the rounded ends of the cells 

 fashion themselves into the rhomboidal* pyramids, "a la suite de 

 I'amincissement progressif des cloisons communes, et des pressions 

 antagonistes exercees sur les deux faces de ces cloisons." 



Among other curious and instructive observations, M. Willem has 

 watched the bees at work on the waxen "foundations" now com- 

 monly used, on which a rhomboidal pattern is impressed with a 

 view to starting the work and saving the labour of the bees. The 

 bees (he says) disdain these half-laid foundations of their cells; they 

 hollow out the wax, erase the rhombs, and turn the pyramidal 

 hollows into hemispherical "cuvettes" in their usual way; and the 

 vertical walls which they raise, more or less on the lines laid down 

 for them, are not hexagonal but cylindrical to begin with. "La 

 forme plane, en facettes, tant de prismes que des fonds, n'est obtenue 

 que plus tard, progressivement, comme resultat de retouches, 

 d'enlevements et de pressions exercees sur les cloisons qui s'amin- 

 cissent, par des groupes d'ouvrieres operant face a face, de maniere 

 antagoniste." 



But when all is said and done, it is doubtful whether such 

 retouches, enlevements and pressions antagonistes, such mechanical 

 forces intermittently exercised, could produce the nearly smooth 

 surfaces, the all but constant angles and the close approach to a 

 minimal configuration which characterise the cell, whether it be 

 constructed by the bee of wax or by the wasp of papery pulp. 

 We have the properties of the material to consider; and it seems 

 much more Ukely to me that we have to do with a true tension 

 effect: in other words, that the walls assume their configuration 

 when in a semi-fluid state, while the watery pulp is still liquid or 

 the wax warm under the high temperature of the crowded hive. 

 In the first few cells of a wasp's comb, long before crowding and 

 mutual pressure come into play, we recognise the identical con- 

 figurations which we have seen exhibited by a group of three or 

 four soap-bubbles, the first three or four cells of a segmenting 

 egg. The direct efforts of the wasp or bee may be supposed to be 

 limited, at this stage, to the making of little hemispherical cups, 

 as thin as the nature of the material permits, and packing these 

 little round cups as close as possible together. It is then con- 

 ceiv ble, and indeed probable, that the symmetrical tensions of the 



