MODERN EVOLUTION. jjo 



else that Wallace did pales before the great discovery 

 which links his name with Darwin's — was the estab- 

 lishment of a line, known as " Wallace's," which 

 divides the Malay Archipelago into two main groups, 

 " Jndo-Majay sia and Austro-Malaysia, marked by 

 distinct species and groups of animals." That line 

 runs through a deep channel separating the islands 

 of Bali and Lombok; the plants and animals on 

 which, although but fifteen miles of water separate 

 them, differ from each other even more than do the 

 islands of Great Britain and Japan. " A similar 

 line, but somewhat farther east, divides on the whole 

 the Malay from the Papuan races of man." 



Among the more fugitive contributions which 

 mark Mr. Wallace's approach to a solution of the 

 problem in quest of which he and Bates went to the 

 Amazons is a paper On the Law which has Regu- 

 lated the Introduction of New Species, published in 

 the Annals and Magazine of Natural History, 1855. 

 In this he shows that some form of evolution of one 

 species from another is needed to explain the geo- 

 logical and geographical facts of which examples are 

 given. 



In the interesting preface to the reprint of the 

 famous paper On the Tendencies of Varieties to de- 

 part Indefinitely from the Original Type, Mr. Wal- 

 lace recites the several researches which he made in 

 quest of that " form " till, when lying ill with fever at 

 Ternate, in February, 1858, something led him to 

 think of the " positive checks " described by Malthus 



