Alfred Russel Wallace 



existence coincident both in time and space with a pre- 

 existing closely allied species," connects together and ren- 

 ders intelligible a vast number of independent and hitherto 

 unexplained facts. The natural system of arrangement of 

 organic beings, their geographical distribution, their geo- 

 logical sequence, the phenomena of representative and 

 substituted groups in all their modifications, and the most 

 singular peculiarities of anatomical structure, are all ex- 

 plained and illustrated by it, in perfect accordance with 

 the vast mass of facts which the researches of modern 

 naturalists have brought together, and, it is believed, not 

 materially opposed to any of them. It also claims a 

 superiority over previous hypotheses, on the ground that it 

 not merely explains but necessitates what exists. Granted 

 the law, and many of the most importa-nt facts in nature 

 could not have been otherwise, but are almost as necessary 

 deductions from it as are the elliptic orbits of the planets 

 from the law of gravitation. 



Some time after the appearance of this article, Wal- 

 lace was informed by his friend and agent, Mr. Stevens, 

 that several naturalists had expressed regret that he was 

 ^* theorising," when what " was wanted was to collect 

 more facts." Apart from this the only recognition which 

 reached him in his remote solitude was a remark in an 

 approving letter from Darwin {see p. 129). 



As Wallace wrote nothing further of importance until 

 the second essay which more fully disclosed his view of 

 the origin of species, we will now briefly trace the growth 

 of the theory of Natural Selection up to 1858, as it came 

 to Darwin. 



It is well known that during Darwin^s voyage in the 

 Beagle he was deeply impressed by discovering extinct 

 armadillo -like fossil forms in South America, the home of 

 armadilloes, and by observing the relationship of the plants 

 and animals of each island in the Galapagos group to those 



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