He took a deep interest, he tells us, in the study of the various races of mankind.  His accounts of the Amazonian tribes suffered greatly by the loss of his journals; but of the peoples of the Malay Archipelago he has given us a most interesting narrative, detailing their bodily and mental characteristics, and showing how their distribution accorded with that of the fauna on the opposite sides—­Malays to the West, Papuans to the East—­of Wallace’s Line.  If fuller investigation of the New Guinea tribes requires some modification in regard to their origin, his observations, as broadly outlined then, remain true still.  His opinions on the origin of the Australian aborigines—­that they were a low and primitive type of Caucasian race—­which, when first promulgated, were somewhat sceptically received, are now those accepted by many very competent anthropologists.

Wallace’s contributions to Geographical Science were only second in importance to those he so pre-eminently made to biology.  Though skilled in the use of surveying instruments, he did little or no map-making—­at all times a laborious and lengthy task—­for, with more important purposes in his mind, he could not spare the time, nor did the limitations to his movements permit any useful attempt.  Yet he did pure geographical work quite as important.  The value of the comparative study of the flora and fauna of neighbouring regions, the great differences in the midst of much likeness between the organic life of neighbouring land masses, was a subject that was always in Wallace’s mind during his exploration of the Amazon Valley, for he perceived that the physical geography and the distribution of these animals and plants were of the greatest service in elucidating their history where the geological record was defective.  As is well known, the visual inspection of the geological structure of tropical countries is always difficult and often impossible to make out because of the dense vegetation upon the surface and even the faces of the river gorges.  But for the loss of his collections and notes we should have had from Wallace’s pen a Physical History of the Amazon.  This loss was, however, amply made up by his very original contributions to the geography of the Malay Archipelago.  “The Zoological Geography of the Malay Archipelago” and “The Physical Geography of the Malay Archipelago” (written on Eastern soil, with the texts of his discourses around him) were the forerunners of his monumental “Geographical Distribution of Animals,” elaborated in England after his return.  “To the publication of the ’Geographical Distribution of Animals’ we owe the first scientific study of the distribution of organic life on the globe, which has broadened ever since, and continues to interest students daily; his brilliant work in Natural History and Geography ... is universally honoured,” are the opinions of Dr. Scott speaking as President of the Linnean Society of London.