This predicted diminution of the size of the jaws and the teeth goes hand in hand with a reduction in the muscle masses which control the masticatory movements of the mandible. Since the cheek bones and their lateral arches serve to enclose these muscles and to take up the pressure created in chewing, it is apparent with a less vigorous mastication and a decrease in the muscle mass that the facial parts will likewise undergo a modification. “Homo futurus” will have, therefore, in addition to his other characteristics, a relatively smaller face.
I mentioned previously that the skull base has shown a marked decrease in modern man. There is a good architectural reason for this. The base of the skull is intimately associated with the face which is linked to it. In fact, it might better be said that the base of the skull is determined by the needs of the facial structure for attachment. Since it is well known that the face has gradually become reduced in length and in horizontal projection, it follows that its field of attachment on the skull base has shown a correlated reduction. Other things being equal, a shorter cranial base means a rounder head. But the decreasing length of the skull base and its facial attachment has another significance here. It calls attention to the marked recession of the face which is so definite in man’s phylogeny. In the primates the jaws project like a muzzle and are labelled prognathic. But in modern Europeans the profile of the jaws has receded to a vertical line dropped from the root of the nose, a condition known as orthognathism. From what has been prophesied already for the man of the future it is clear that this recession will be emphasized to an even greater degree.
Let us turn to another attribute of our average man of 500,000 years from now. This future being will be taller than we are. My reasons for this belief are in reality simple. It is, in the first place, well known that in many forms of evolving species there is a definite increase of size during the course of their evolution. The giant reptilian forms of the Mesozoicthe dinosaurs, the brontosaurs and their relatives—all began as small forms and gradually put on weight. One of these ponderous creatures might well have looked back to its phylogenetic youth and sung with sadness:
“Fading is the taper waist, Shapeless grows the shapely limb, And although severely laced, Spreading is the figure trim! Stouter than I used to be, Still more corpulent grow I. There will be too much of me In the coming bye and bye— There will be too much of me In the coming bye and bye.”
Indeed this phenomenon is a common one. We see it again in the phylogeny of the horse, the camel, and in various other mammals. In the primates, too, the sequence runs from the small lemuroid creatures to the hefty gorillas. Now, in man it has likewise been observed that the stature of early man is often near the upper limits of pygmy stature whereas we overtop them considerably. Projecting this trend into the future we must anticipate an increasingly taller and bigger man. But there is other evidence to support this prophecy. In many forms of evolving species there is a definite increase of size during the course of their evolution. The giant reptilian forms of the Mesozoic —the dinosaurs, the brontosaurs and their relatives—all began as small forms and gradually put on weight. Everywhere in Europe and in America where records have been maintained over a period of years, there has been a consistent accretion to the average stature. Investigators of this phenomenon have reported such an increase in Switzerland, Germany, Sweden, Denmark, Holland, England, and the United States. It would be tedious to reproduce here all the figures which corroborate this general phenomenon, but we may illustrate it by a few examples. In the Canton St.–Marie Vesubie, in the Maritime Alps, the average stature has increased from 155.5 cm. in 1792 to 165.0 cm. in 1872. In Norway an increase has been reported from 168.6 cm. in 1850 to 170.7 in 1905. Perhaps the best illustration of this remarkable increase in stature, and the most convincing, is the study of successive generations of Harvard students which has recently been issued by G. T. Bowles. Dealing with sons, fathers, and in some cases grandfathers, all belonging to one class in society, he was thereby able to eliminate such factors as social and economic influences. Furthermore, there was no question here of differences in stock. The results unequivocally support the findings already mentioned. The present generation is about 3.55 cm. taller than their own fathers, younger sons are somewhat taller than their elder brothers, and the fathers are taller than the grandfathers. Just exactly what is causing this no one knows precisely. None of the numerous reasons suggested by the fertile imagination of a number of workers seem to be completely satisfactory. A fresh opinion from Switzerland proposes that the intensity of modern life stimulates the vegetative nervous system which in its turn reacts on the increase of growth. Hooton has ingeniously suggested that modern hygiene and medicine are able to nurse to maturity the rapidly growing tall children who formerly tended to be eliminated. But whatever the true nature of this change—whether nervous or medical—since I see no permanent nor complete relapse to barbarity with a consequent return to a simpler life and a destruction of medical science, I therefore predict a taller man in the future. I frankly halt at attempting to estimate the number of his inches. As a prophecy this should please many of my patient readers, but I do not see it as an unmixed blessing. As far as I know, there is no reason why a taller man is mechanically a better one. As a matter of fact, a short man is probably more efficient in the use of the energy which his body creates than a tall one. But esthetically the tall men are preferred, as least, among Europeans and Americans and perhaps in a civilized nation Art should prevail.
We now have the major aspects—the high lights—of the portrait of our future man. At any rate these are all I have space to expand upon. I shall now turn to a few of the details which give character and individuality to our drawing.