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wallace.online.org
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.174 NATURAL SELECTION vintherefore, have become the subjects of natural selection.For it is evident that such qualities would be for the wellbeingof man, would guard him against external enemies,against internal dissensions, and against the effects of inclementseasons and impending famine, more surely than couldany merely physical modification. Tribes in which suchmental and moral qualities were predominant would thereforehave an advantage in the struggle for existence overother tribes in which they were less developed would liveand maintain their numbers, while the others would decreaseand finally succumb.Again, when any slow changes of physical geography orof climate make it necessary for an animal to alter its food,its clothing, or its weapons, it can only do so by the occurrenceof a corresponding change in its own bodily structureand internal organisation. If a larger or more powerfulbeast is to be captured and devoured, as when' a carnivorousanimal which has hitherto preyed on antelopes is obliged fromtheir decreasing numbers to attack buffaloes, it is only thestrongest who can hold, those with most powerful clawsand formidable canine teeth that can struggle with and overcomesuch an animal. Natural selection immediately comesinto play, and byits action these organs gradually becomeadapted to their new requirements. But man, under similarcircumstances, does not require longer nails or teeth, greaterbodily strength or swiftness. He makes sharper spears, or abetter bow, or he constructs a cunning pitfall, or combines ina hunting party to circumvent his new prey. The capacitieswhich enable him to do this are what he requires to bestrengthened, and these will, therefore, be gradually modifiedby natural selection, while the form and structure of hisbody will remain unchanged. So, when a glacial epoch comeson, some animals must acquire warmer fur, or a covering offat, or else die of cold. Those best clothed by nature are,therefore, preserved by natural selection. Man, under thesame circumstances, will make himself warmer clothing, andbuild better houses, and the necessity of doing this will reactupon his mental organisation and social condition will advancethem while his natural body remains naked as before.When the accustomed food of some animal becomes scarce^jj

via THE DEVELOPMENT OF HUMAN RACES 175or totally fails, it can only exist by becoming adaptedkind of food, a food perhaps less nourishing and less digestible.Natural selection will now act upon the stomach and intestines,and all their individual variations will be taken advantageof, to modify the race into harmony with its new food.In many cases, however, it is probable that this cannot bedone. The internal organs may not vary quick enough, andthen the animal will decrease in numbers and finally becometo a newextinct. But man guards himself from such accidents bysuperintending and guiding the operations of nature. Heplants the seed of his most agreeable food, and thus procuresa supply, independent of the accidents of varying seasons ornatural extinction. He domesticates animals, which serve himeither to capture food or for food itself, and thus changes ofany great extent in his teeth or digestive organs are renderedunnecessary. Man, too, has everywhere the use of fire,andby its means can render palatable a variety of animal andvegetable substances, which he could hardly otherwise makeuse of, and thus obtains for himself a supply of food farmore varied and abundant than that which any animal cancommand.Thus man, by the mere capacity of clothing himself, andmaking weapons and tools, has taken away from nature thatpower of slowly but permanently changing the external formand structure in accordance with changes in the externalworld, which she exercises over all other animals. As thecompeting races by which they are surrounded the climate,the vegetation, or the animals which serve them for food areslowly changing, they must undergo a corresponding changein their structure, habits, and constitution to keep them inharmony with the new conditions to enable them to liveand maintain their numbers. But man does this by meansof his intellect alone, the variations of which enable him, withan unchanged body, still to keep in harmony with the changinguniverse.There is one point, however, in which nature will still actupon him as it does on animals, and, to some extent, modifyhis external characters. Mr. Darwin has shown that the colourof the skin is correlated with constitutional peculiarities bothin vegetables and animals, so that liability to certain diseases

via THE DEVELOPMENT OF HUMAN RACES 175or totally fails, it can only exist by becoming adaptedkind of food, a food perhaps less nourishing and less digestible.Natural selection will now act upon the stomach and intestines,and all their individual variations will be taken advantageof, to modify the race into harmony with its new food.In many cases, however, it is probable that this cannot bedone. The internal organs may not vary quick enough, andthen the animal will decrease in numbers and finally becometo a newextinct. But man guards himself from such accidents bysuperintending and guiding the operations of nature. Heplants the seed of his most agreeable food, and thus procuresa supply, independent of the accidents of varying seasons ornatural extinction. He domesticates animals, which serve himeither to capture food or for food itself, and thus changes ofany great extent in his teeth or digestive organs are renderedunnecessary. Man, too, has everywhere the use of fire,andby its means can render palatable a variety of animal andvegetable substances, which he could hardly otherwise makeuse of, and thus obtains for himself a supply of food farmore varied and abundant than that which any animal cancommand.Thus man, by the mere capacity of clothing himself, andmaking weapons and tools, has taken away from nature thatpower of slowly but permanently changing the external formand structure in accordance with changes in the externalworld, which she exercises over all other animals. As thecompeting races by which they are surrounded the climate,the vegetation, or the animals which serve them for food areslowly changing, they must undergo a corresponding changein their structure, habits, and constitution to keep them inharmony with the new conditions to enable them to liveand maintain their numbers. But man does this by meansof his intellect alone, the variations of which enable him, withan unchanged body, still to keep in harmony with the changinguniverse.There is one point, however, in which nature will still actupon him as it does on animals, and, to some extent, modifyhis external characters. Mr. Darwin has shown that the colourof the skin is correlated with constitutional peculiarities bothin vegetables and animals, so that liability to certain diseases

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