162 EVOLUTION 



operation of natural selection. The theory 

 works well as an interpretation, but what 



We need IS a^fyjal prnnf of rl^pQrm'rj^^ 



selection, actual evidence that survivors 

 do survive in virtue of particular qualities. 

 A few examples of this in present-day ex- 

 perience will give strength to the belief that 

 similar processes occurred, as Darwin sug- 

 gested, throughout the past. 



It is interesting to note that so strong 

 a selectionist as Weismann considers that 



frrly . in- 



directly. He says: "A direct estimation of 

 the relative protective value of the two 

 colours [of a Sphingid caterpillar] is alto- 

 gether out of the question. The_ survival 

 of the fittppt p^nnt K^ proved jji nature. 



Simply hpffl.-n<gp..wp QTV* ruit in Q prtgjfjpft f^ 



clecMp..juprieri what th<JtofiatJa" As Mr. 

 E. S. Russell remarks: "This is a significant 

 admission from the protagonist of pure 

 Darwinism, but he admits too much. It is 

 true we cannot decide a priori what the fittest 

 is, but WP pflTi^iftppy^f fry nhfifirvatifiTi 

 t^ whether o,r 



ie. A case in point 

 is given by Mr. A. P. di Cesnola in a short 

 but highly interesting paper in 'Biometrika' 

 for 1904. 



"It is well known that the * praying 



