8 Alfred Russel Wallace, LL. D. 



In 1878 Dr. Wallace published his two volumes On the 

 Geographical Distribution of Animals. His original re- 

 searches on the distribution of animals in the Malaysian 

 Archipelago furnished the starting point of this work. It 

 is an excellent general exposition of the subject, which has, 

 however, from the nature of the case, become in some 

 points superannuated. The systematic relations of many 

 groups of animals are now better understood than they 

 were then, and paleontology has made great advances be- 

 yond the state of knowledge recorded in this work. In 

 1878 the work of a popular character on Tropical Nature 

 appeared. His book on Island Life was published in 1880. 

 Here we have a discussion of the faunae of islands, a very 

 fertile subject in the evidence it contributes to questions of 

 distribution in past and present time, and in the restricted, 

 and therefore more comprehensible, fields which it offers for 

 the solution of questions of subsistence, selection, etc. He 

 here brings into final order the evidence as to the primitive 

 separation of the Oriental and Australian faunae which now 

 approach each other so closely in the Malaysian Islands. 

 He found during his residence in Malaysia that the islands 

 of the respective groups were separated from each other by 

 comparatively shallow seas, while a deep channel divides the 

 two groups as a whole from each other. This channel, 

 which passes between Celebes and Borneo at the northwest, 

 and Lombok and Bally at the southwest, is known as Wal- 

 lace's Channel. The fauna of Celebes is, however, some- 

 what intermediate in possessing some types of both faunas. 



In 1889 Dr. Wallace's last work, Darwinism, appeared. 

 In this book he summarizes the facts and inferences which 

 bear on evolution. As before, natural selection is regard- 

 ed as the leading factor in structural evolution. The sub- 

 jects treated of are arranged in the following order : Chap- 

 ter I. What are Species, and what is meant by their Ori- 

 gin. II. The Struggle for Existence. III. The Variability 

 of Species in a State of Nature. IV. Variations of Domes- 

 tic Animals and Cultivated Plants. V. Natural Selection 

 by Variation and Survival of the Fittest. VI. Difficulties 

 and Objections. VII. Infertility of Crosses between Dis- 

 tinct Species, and the Usual Sterility of Hybrids. VIII. 

 The Origin and Uses of Color in Animals. IX. Warning 

 Coloration and Mimicry. X. Colors and Ornaments Char- 

 acteristic of Sex. XI. Special Colors of Plants, their Ori- 

 gin and Purpose. XII. The Geographical Distribution 



