The same fact can be noticed for the external characteristics of man, such as the colour of the skin, the colour and form of the hair, and the colour of the iris. It is solely in the crossings that there can be intermediary formations which have not indefinite heredity, because the segregation of characteristics takes place also in this case.
But the studies and observations on this matter are still incomplete, especially according to the Mendelian theory, and there is need of new and careful observation.
As to the pathological inheritance, there exist facts that confirm it in a general way, but the laws under which this heredity occurs have not been fully verified.
[ON THE INCREASE OF STATURE IN CERTAIN EUROPEAN POPULATIONS.]
(Abstract.)
By Soren Hansen, M.D.,
Director of the Danish Anthropological Survey, Copenhagen.
The improvement in stature in many European countries during the past 50 years is generally ascribed simply to improved hygienic and economic conditions, but the question is really very intricate. The presence of different racial elements, social selection with its tendency to draw the well-made into towns, and the falling death-rate, etc., complicate the investigations. In all countries there is a great lack of truly comparable data from earlier years. The British Inter-Departmental Committee on Physical Deterioration, for example, though it collected an enormous amount of material, was unsuccessful in its endeavours to solve the main question. Single cases, e.g., the comparison of factory children with the boys of the York Quaker school (Anthropometric Committee, Brit. Ass. 1883), are certainly of great interest, but how can such cases be taken to represent the average?
Other countries possess a rich source of information in their conscription lists. Thus, in Denmark these lists show an unmistakable increase of 3.7 cm. (11/2 inch) in the average height of the adult Dane during the past 50-60 years. Similar increases are noted from Norway, Sweden and Holland. This increase suggests that there may have been more or less periodic waves of increase and decrease in height, since, on the one hand, we cannot imagine such an increase continuing indefinitely, and on the other, we know that the men of, say, 1000 years ago were quite as tall as they are at present. What are the agencies alternately improving or impairing the racial qualities? First of all, have we sufficiently exact, numerical information regarding the racial qualities?
A critical examination of all available data is very necessary. For example, the weight of new-born children is stated to have increased in England by 59 and 82 grams during the past 20 years, and in Denmark we can point to an increase of 40 grams in 35 years. But when we consider all the possible sources of error, it must be admitted that these statements, and especially the former, require confirmation. The material is not homogenous. Again, it is stated, that the average height of adult women in France has increased by 3 cm. in the last 80 years—but when we read that the total number of measurements in the last period was only 255, we cannot rely very much upon this statement.