Page:Popular Science Monthly Volume 31.djvu/371

Rh 25·21 grammes less than the Roumani. The South Slavonian brains are somewhat heavier than the Italian, but lighter than any of the other peoples. One third of the Austrian Empire is peopled by Germans, descended from the natives of Austria proper. The Magyars are Asiatics of the Mongolian race. The South Slavonians occupy the most southern part of the empire, along the low-lying lands of the Danube, which accounts for the small size of their brains; while the Italians are descended from the inhabitants of a still warmer region; all which goes to confirm the theory we have already announced, that the smallest brains belong to the warmest climates. "On comparing the peoples of the four families represented here," continues Dr. Wiesbach, "we find that the Slavonic family possess the largest encephalon, the Romanic the smallest; and that the intermediate Magyars possess a more weighty encephalon than the Germans, which are nearly equal to the Romanic stock."

In a recently-published work Professor Bischoff, an eminent anatomist at Munich, gives the average brain-weight of males as forty-eight ounces ("Nature," January 20, 1881) after weighing five hundred and fifty-nine subjects, the obvious reason for the discrepancy between him and the authors above mentioned being the fact that Munich, situated in the southern part of Germany, is warmer than either Edinburgh or New York.

Dr. Tiedemann, of Heidelberg, on the Alpine plateau of the Rhine in Germany, where it is far colder than Edinburgh in winter, gave the average male brain-weight, for the whole of life above puberty, as 53·25 ounces. Sir W. Hamilton, of Edinburgh, estimated the average adult brain, without distinction of health or disease, at 48·25 ounces, for the whole of life. In London, Dr. Sims found it 46·25 ounces. Luschka gives 50·2 ounces as the average weight of a man's brain; Krause makes it 55·4 ounces, according to an article in the "Morning Herald," Sydney, Australia.

The above averages differ, from several causes. Dr. Tiedemann's observations were limited to fifty-two subjects, and included both sexes, but excluded negroes and very aged persons. Sir W. Hamilton had sixty or seventy of both sexes; Dr. Sims, two hundred and twenty; and Dr. Clendinning still more than Dr. Sims, whose patients were largely among the aged, and those afflicted with long-standing disease. Dr. Clendinning, in the Croonian Lectures, gives the following brain-weights from male subjects, which show that the male encephalon loses more than an ounce every ten years after it is fully grown:

Several other eminent anatomists have made similar exhibits—brain-weight decreasing as the intellectual power increases. It is