2 1 2 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 



