252 THE CASE AGAINST EVOLUTION 



the bee was then engaged. In a word, if the damage inflicted 

 could be repaired by a simple continuation or extension of its 

 actual work of the moment, the bee was able to cope with the 

 emergency. There are other ways, too, in which the animal 

 adapts its constructive instincts to external circumstance. 

 Fabre tells us that the Bramble-bee Osmia, which 

 builds a train of partitioned cells in snail shells or in hol- 

 low reeds, will victual first and then plaster in a 

 partition, if the reed be narrow, but will first plaster 

 a partition, and then introduce honey and pollen through a 

 hole left unclosed in the partition, whenever the reed is of 

 greater diameter. This reversal of the procedure according 

 to the exigencies of the external situation does not suggest 

 the chain-reflex of Loeb. (Cf. "The Bramble-Bee," pp. 214- 

 217.) Another kind of adaptation of instinct to external cir- 

 cumstances consists in the economical omission of the initial 

 step of a serial construction, in cases where the environ- 

 mental conditions provide a ready-made equivalent. "The 

 silkworm," says Driesch, "is said not to form its web of silk 

 if it is cultivated in a box containing tulle, and some species 

 of bees which normally construct tunnels do not do so if they 

 find one ready made in the ground, they then only perform 

 their second instinctive act: separating the tunnel into single 

 cells." ("Science & Phil, of the Organism," vol. II, p. 47.) 



Driesch's analysis of the constructive instinct shows that 

 these facts of adaptation or regulation fit in with the idea of 

 sensory control rather than with that of a chain-reflex. In 

 the supposition that the successive stages of instinctive con- 

 struction are due to a chain-reflex, consisting of a series of 

 elementary motor reactions a, h, c, etc., in which a produces 

 the external work A and, on terminating, releases b, which, in 

 turn, produces external work B and releases c, et€., clearly h 

 could never appear before a, and the sight of A ready-made 

 would not inhibit a, nor would the removal of A defer the 

 advent of h. In other words, regulation would be impossible. 

 But, if we suppose that not the elemental act a, but rather 



