128 PIONEERS OF EVOLUTION PART 



numerous papers communicated to learned societies 

 and scientific journals, and in a series of delightful 

 books from The Malay Archipelago, first published 

 in 1869, to Island Life, published in 1880. Among 

 the minor results of his extensive travels for all 

 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, * Indo- 

 Malaysia 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 Regulated 

 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 

 geological 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 depart 

 Indefinitely from the Original Type, Mr. Wallace recites 

 the several researches which he made in quest of that 

 * form ' till, when lying ill with fever at Ternate, in 



