Modern travellers have reduced to accurate proportions the exaggerated statements of ancient navigators. The French naturalist Alcide d’Orbigny actually measured a large number of Patagonians, and found that their height, on an average, was about 1m.73.
This, then, is about the limit of the height which is reached by the human species.
With reference to the extreme of smallness we are able to arrive at this by referring to the Bushmen who inhabit Southern Africa. An English traveller, Barrow, measured all the members of a tribe of Bushmen, and found that their average height was 1m.31.
The human species, therefore, varies in height to the extent of about 0m.42, that is to say, the difference between the height of the Patagonians and that of the Bushmen. It is well to make this observation whilst we are upon this subject, since the supporters of the theory of a plurality of human races have invoked these differences in height in support of the multiplicity of the races of humanity. It is clear that, among animals, races vary in height to a much greater extent than they do with man; there is, by comparison, a much greater difference in size between a mastiff and a dog of the Pyrenees, than there is between a Bushman and a Patagonian.
As regards the colour of the skin of the human race, we find it necessary to say a few words, since we propose to take this as the basis of our classification.
The colour of the skin is a very convenient characteristic to fix upon in order to identify the various races, since this quality is peculiarly adapted to suggest itself through the eye. Its scientific importance must, however, by no means be exaggerated. Certain individuals, though they be members of the White or Caucasian Race, may yet be very darkly tinted. Arabs are often of a brown colour, which nearly approaches black, and yet they possess the finest marks of the White or Caucasian Race. The Abyssinians, although very brown, are not black. The American Indians, whom we rank as members of the Red Race, often have dark brown or almost black skins. Among members of the White Race in northern latitudes, especially women, the skin has often a yellowish tint. We must add that the colour of the skin is often difficult to fix, since the shades of colour merge into one another. All this must be said in order to show how difficult it is to form natural groups of the innumerable types of our species.
It would be for us now to speak of the physiological characteristics of the human race; but our consideration of this subject will be limited to a few words, since the condition of physiological functions is almost identical among all men, whatever be their race.
There is, nevertheless, an important difference, well worthy of note, presented by the nervous system when we compare the two extremes of humanity, namely, the Negro and the white European. In the white man, the nervous centres, that is the brain and spinal cord, are of much greater volume than they are in the Negro. In the latter the expansions from these nervous centres, that is, the nerves properly so called, have relatively a greater volume.
A similar difference, quite on a par with this, exists in the circulatory system. In the white man, the arterial system is more developed than the venous; the reverse is the case with the Negro. Lastly, the blood of the Negro is more viscous, and of a deeper red than that of the white man.
With the exception of these general differences, the great physiological functions proceed in the same manner among all races of men. The differences are not remarked except when secondary functions are compared, but these differences then assume proportions of some consideration.