212 Animal Life and Intelligence. 



We have seen that certain insects are possessed of 



warning colours, which advertise their nastiness to the 



taste. Birds avoid these bright but unpleasant insects, 



and though there is some individual learning, there seems 



to be an instinctive avoidance of these unsavoury morsels. 



There is hesitation before tasting; and one or two trials 



are sufficient to establish the association of gaudiness and 



nastiness. Moreover, Mr. Poulton and others have shown 



that, under the stress of keen hunger, these gaudy insects 



may be eaten, and apparently leave no ill effects. Birds 



certainly instinctively avoid bees and wasps ; and yet the 



sting of these insects can seldom be fatal. It is, therefore, 



improbable that nastiness or even the power of stinging 



can have been an eliminating agency. In the development 



of the instinctive avoidance, natural selection through 



elimination seems to be excluded, and the inheritance of 



individual experience is thus rendered probable. As before 



pointed out, it is not enough to say that a nasty taste or a 



sting in the gullet is disadvantageous; it must be shown 



that the disadvantage has an eliminating value. From 



my experiments (feeding frogs on nasty caterpillars, and 



causing bees to sting chickens), I doubt the eliminating 



value in this case. Hence elimination by natural selection 



seems, I repeat, to be excluded, and the inheritance of 



individual experience rendered probable. 



Mr. Herbert Spencer has contended that, in certain 

 modifications, natural selection is excluded on the grounds 

 of the extreme complexity of the changes, and adduces the 

 case of the Irish " elk " with its huge antlers, and the giraffe 

 with its specially modified structure. He points out that 

 in either case the conspicuous modification the gigantic 

 antlers or the long neck involves a multitude of changes 

 affecting many and sometimes distant parts of the body. 

 Not only have the enormous antlers involved changes in 

 the skull, the bones of the neck, the muscles, blood-vessels, 

 and nerves of this region, but changes also in the fore 

 limbs ; while the long neck of the giraffe has brought with 

 it a complete change of gait, the co-ordinated movements 



