CHAPTER X
THE APPLICATION OF BIOMETRY TO ANTHROPOLOGY FOR THE PURPOSE OF DETERMINING THE MEDIAL MEN
Theory of the Medial Man.—Measurements are used not only in anthropology but in zoology and botany as well; that is, they are applied to all living creatures; therefore anthropometry might to-day be regarded as a branch of biometry. The measurements obtained from living beings, and the statistical and mathematical studies based upon them, tend to determine the normality of characteristics; and when the biometric method is applied to man, it leads to a determination of the normal dimensions, and hence of the normal forms, and to a reconstruction of the medial man that must be regarded as the man of perfect development, from whom all men actually existing must differ to a greater or less extent, through their infinite normal and pathological variations.
This sort of touch-stone is of indisputable scientific utility, since we cannot judge of deviations from the norm, so long as normality is unknown to us. In fact, when we speak of normality and of anomalies, we are using language that is far from exact, and to which there are no clear and positive corresponding ideas.
Whatever has been accomplished in anthropology up to the present time in the study of the morphology of degenerates and abnormals, has served only to illustrate this principle very vaguely—that the form undergoes alteration in the case of pathological individuals. It is only now that we are beginning to give definite meaning to this principle, by seeking to determine what the form is, when it has not undergone any alteration at all. From this fundamental point a new beginning must be made, on more certain and positive bases, of the study of deviations from normality and their etiology.
As far back as 1835, Quétélet, in his great philosophical and statistical work, Social Physics or the Development of the Faculties of Man, for the first time expounded the theory of the "medial man," founded on statistical studies and on the mathematical laws of errors. He reached some very exact concepts of the morphology of the medial man, based upon measurements, and also of the intellectual and moral qualities of the medial man, expounding an interesting theory regarding genius.
But inasmuch as Quétélet's homme moyen was, so to speak, at once a mathematical and philosophical reconstruction of the non-existent perfect man, who furthermore could not possibly exist, this classical and masterly study by the great statistician was strenuously combatted and then forgotten, so far as its fundamental concepts were concerned, and remembered only as a scientific absurdity. The thought of that period was too analytical to linger over the great, the supreme synthesis expounded by Quétélet.
Mankind must needs grow weary of anatomising bodies and tracing back to origins, before returning to an observation of the whole rather than the parts, and to a contemplation of the future. In fact, the thought of the nineteenth century was so imbued with the evolutionary theories as set forth by Charles Darwin, that it believed the reconstruction of the Pithecanthropus erectus from a doubtful bone a more positive achievement than that of the medial man from the study of millions of living men.
But to-day the researches that we have accomplished in the biological field regarding evolution, regarding natural heredity, regarding individual variability, are leading biology as a whole toward eminently synthetic conclusions; and studies which remained neglected or which were combatted in the past, are beginning to be brought into notice and properly appreciated: such studies, for instance, as Mendel's theory and that of Quétélet. Galton, Pearson, Davenport, Dunker, Heinke, Ludwig, and above all others De Vries, are in the advance guard of modern biological thought. But beyond all these scientists, there is one who has an interest for us not only because he is an Italian, but because he has reestablished Quétélet's ancient theory of the medial man, under the present-day guidance of biometry: I mean Prof. Giacinto Viola.
The Importance of Seriation.—Under the statistical method, the basis of biometry is furnished by a regrouping of measurements in the form of series. We have seen that Quétélet's binomial curve represents the symmetrical distribution of subjects in relation to some one central anthropometric measurement.