Page:Popular Science Monthly Volume 59.djvu/408

398 for the results of their observations in their own countries in regard to all classes of people. He at length published a symposium of the answers showing the prevalence of trachoma in different countries and among the different classes of people. As given in this contribution there seemed to be a confused accumulation of facts which had, on the whole, apparently little meaning. Peoples of contiguous countries, of the same color and not very different in habits of life, were reported as differing widely in respect to the prevalence of the affection. No reasons were assigned and none seemed to be suggested by the varying facts. An analysis which I made of this report showed that among peoples with the 'medium' or tall heads, like the Irish and the Italians, trachoma is rife; while among peoples with the broad head, like the Bavarians, or with the long head, like the negroes whose ancestors were from the West or Guinea coast of Africa, trachoma did not prevail; but it is interesting to note that descendants of the negroes of the northern part of Africa, where the heads of the natives are often tall, are subject to trachoma equally with the whites among whom they live. I have in another connection discussed this question at more length.

A glance at Fig 14 will show that the negro as he is known in our Southern States not only throws the head backward in the manner characteristic of the long head, the strong facial angle and the depressed visual plane, but that the eyebrows are characteristically elevated. This drawing up of the brow is accompanied with a drawing upon the lids and hence no pressure is brought upon the surface of the eyes by the upper lids. In the case of the tall head with the high plane of vision the brows are strongly compressed and the lids bind upon the eyeball and thus in the midst of dust and filth or even in good sanitary surroundings disease of the lids may be promoted. Reverting once more to the declinations of the retinal meridians, the same effect may be induced both as to the pose of the head and the relaxed state of the lids. It is, however, impracticable to consider the subject from that point of view at present.

Turning to a larger and more important subject, the negro is known to be especially subject to tubercular diseases, yet he is, to an unusual degree, immune from consumption. In my investigations during the past few years, I have not seen a consumptive the direction of whose visual plane was not much higher than the standard. We shall come to this from another point of view. It is easy to see that