86 Barbour, Tin c<i*c of Roosevdt vs. Thayer. 



Auk 

 .Ian. 



thai foxes and dogs may locate their prey by scout, that this 

 may militate seriously against Mr. Thayer's contention that the 

 final spring on all occasions is directed by sight alone. 1 think the 

 important point here really is that we find no evidence that beasts 

 of prey are unable to maintain themselves perfectly successfully 

 in spite of the operation of all these Supposedly adverse conditions. 

 If an animal can get all the food it needs, what more does it want? 

 So much for our remarks on Mr. Allen's paper. They are some- 

 what disjointed and perhaps prolix. We could pick him up on 

 many other points, hut this serves to show that his desire to simply 

 bolster up the arguments oi' a friend would have been more con- 

 vincing had they been more impartially conceived. 



Some time ago, Or. Phillips ami I reviewed Mr. Thayer's book 

 (Aid;. April 1910. We put a number of direct questions to Mr. 

 Thayer at that time which we hoped he would answer, both for his 

 own sake and as an evidence to naturalists in general of his sincere 

 desire to really keep this discussion going, to open up the whole 

 matter of coloration so far as possible, to suggest fields of inquiry 

 and experimentation, and not simply to sit down on the top of a 

 heap o( facts, which he claims to have discovered and take the 

 attitude that the whole business is settled. Mr. Thayer claims to 

 be interested only in what he terms facts, whys and wherefores 

 receive practically no attention. Franklin did not discover 

 lightning, but he proved its causation through its connection with 

 electrical phenomena, and for that reason became very great. 

 The least increment to our knowledge of how differences are 

 brought about by evolution, actual endeavours to prove experi- 

 mentally, if possible, the working of evolution relating to the origin 

 o( coloration would be worth more than many pages devoted to 

 proving that an oryx's head may be well concealed in a pine tree. 

 Since Mr. Thayer published his book, he has given us a figure 

 (Pop. Sci. Mon„ July 101 1, p. 20 showing a lion approaching 

 three antelopes uphill. The 'lion's horizon line' and the level 

 of the plains, 'appearing to meet the level of the lion's eye.' 

 make an angle with each other o( about '20 degrees, and under 

 these conditions, according to the 'great optical principle' which 

 'I have discovered' the antelopes arc rendered invisible to the 

 lion through their counter shading. Supposing, however, that the 



