A Physicist on Evolution. 191 



living tilings produced is far in excess of the number that can be 

 supported ; hence at some period or other of their Hves there 

 must be a struggle for existence ; and what is the infallible result ? 

 If one organism were a perfect copy of the other in regard to 

 strength, skill, and agility, external conditions would decide. But 

 this is not the case. Here we have the fact of variety offering 

 itself to nature, as in the former instance it offered itself to man ; 

 and those varieties which are least competent to cope with sur- 

 rounding conditions will infallibly give way to those that are com- 

 petent. To use a familiar proverb, the weakest comes to the wall. 

 But the triumphant fraction again breeds to over-production, trans- 

 mitting the qualities which secured its maintenance, but transmitting 

 them in different degrees. The struggle for food again supervenes, 

 and those to whom the favourable quality has been transmitted in 

 excess will assuredly triumph. It is easy to see that we have here 

 the addition of increments favourable to the individual still more 

 rigorously carried out than in the case of domestication ; for not 

 only are unfavourable specimens not selected by nature, but they 

 are destroyed. This is what Mr. Darwin calls " natural selection," 

 which " acts by the preservation and accumulation of small inherited 

 modifications, each profitable to the preserved being." With this 

 idea he interpenetrates and leavens the vast store of facts that he 

 and others have collected. We cannot, without shutting our eyes 

 through fear or 23rejudice, fail to see that Darwin is here dealing, 

 not with imaginary, but with true causes ; nor can we fail to 

 discern what vast modifications may be produced by natural selec- 

 tion in periods sufficiently long. Each individual increment may 

 resemble what mathematicians call a " differential " (a quantity 

 indefinitely small) ; but definite and great changes may obviously be 

 produced by the integration of these infinitesimal quantities through 

 practically infinite time. 



If Darwin, like Bruno, rejects the notion of creative power 

 acting after human fashion, it certainly is not because he is un- 

 acquainted with the numberless exquisite adaptations on which this 

 notion of a supernatural artificer was founded. His book is a 

 repository of the most startling facts of this descrij^tion. Take the 

 marvellous observation which he cites from Dr. Criiger, where 

 a bucket with an aperture, serving as a spout, is formed in an 

 orchid. Bees visit the flower : in eager search of material for their 

 combs they push each other into the bucket, the drenched ones 

 escaping from their involuntary bath by the spout. Here they rub 

 theu' backs against the viscid stigma of the flower and obtain glue ; 

 then against the pollen-masses, which are thus stuck to the back of the 

 bee and carried away. " When the bee, thus provided, flies to another 

 flower, or to the same flower a second time, and is pushed by its 

 comrades into the bucket, and then crawls out by the passage, the 



