Disturbance to Proportion of Sexes among the Children. Normal: 106 Generation of sonless fathers: 160 " " " mothers: 93 Key to Table ------------ [A] Normal families. [B] Families in process of extinction. Figure C 44.] [Sidenote: C 45] In this connection another figure, C 45, by von den Velden ought to be mentioned. He shows, from investigations made by von Riffel, that the +physical condition of childless couples is on the average inferior to that of fertile parents+. This, however, by no means holds good in every case. Evidence to the contrary is given by the pedigree of an aristocratic family which has died out in the male line. It may be looked upon as typical. One generation (the second), with three times as many grown up men than women, produces only four boys (44% of the children), of whom two reach maturity. With the fourth generation the male issue dies out. Though a large majority of the members of all three generations (2-4th) have good health and attain to an exceptionally high age, most of the female lines also die out. Only in two branches, which spring from the marriage of an aristocratic daughter with a man from the people, there are children in the fifth generation of whom at least a part promise a healthy progeny. Fahlbeck, too, has drawn attention to the fact that the dying out Swedish aristocracy shows no signs of striking degeneracy in the individual. This fact is of the greatest theoretical and practical importance because it proves that there exists, up to a certain degree, an independent degeneration of the germ plasm, even as the germ plasm may remain unaffected by damage to the soma. That such a one-sided degeneration of the germ plasm with respect to the power of reproduction may take place among animals has been known for a long time. In particular, Chs. Darwin has collected facts of this kind in his "Variation of Animals and Plants under Domestication." For civilised peoples it is a matter for reflection that with animals even slight deviations from their customary "natural" mode of living may lead to such serious consequences. RACE-HYGIENE. [Sidenote: C 46 & 47] As the +nature and aims of race-hygiene+ are still unknown in wide circles it will be useful to show in Tables C 46 and C 47, by A. Ploëtz, what its position is amongst other sciences and what the various branches of its activity consist in.