TABLE XX. -------------------------------------------------- | No. of |Percentage | Cases. |hereditary. -------------------------------------------------- 1. Simple Insanity |102,097 | 31.7 = 100 Consanguineous parentage | 664 | 69.0 = 218 Parents cousins | 595 | 68.1 = 215 Parents uncle and niece | 66 | 77.3 = 244 -------------------------------------------------- 2. Paralytic Insanity | 22,936 | 17.6 = 100 Consanguineous parentage | 95 | 45.3 = 257 Parents cousins | 87 | 44.8 = 255 Parents uncle and niece | 8 | 75.0 = 426 -------------------------------------------------- 3. Epileptic Insanity | 14,067 | 25.6 = 100 Consanguineous parentage | 79 | 53.2 = 208 Parents cousins | 70 | 50.0 = 195 Parents uncle and niece | 9 | 66.7 = 261 -------------------------------------------------- 4. Imbecility and Idiocy | 16,416 | 28.7 = 100 Consanguineous parentage | 237 | 43.0 = 150 Parents cousins | 211 | 43.1 = 150 Parents uncle and niece | 26 | 38.5 = 134 -------------------------------------------------- Table XXI gives the proportion of the mentally defective who are the offspring of consanguineous marriages. The term "cousin" in both these tables probably means first cousins. It will be remembered that Prussian statistics of consanguineous marriages are very imperfect, but that at least 6.5 in every thousand are consanguineous (first cousins or nearer). TABLE XXI.[73] _Parentage of Mental Defectives in Prussia._ ----------------------------------------------------- | Consan- | |Uncle and |guineous.|Cousins.| Niece. ----------------------------------------------------- 1. Insanity (simple) | 6.5[A] | 5.8[A]| .64[A] Hereditary | 14.2 | 12.5 | 1.6 Not hereditary | 3.0 | 2.7 | .22 ----------------------------------------------------- 2. Paralytic Insanity | 4.1 | 3.8 | .35 Hereditary | 11.1 | 9.6 | 1.48 Not hereditary | 2.9 | 2.5 | .11 ----------------------------------------------------- 3. Epileptic Insanity | 5.6 | 4.9 | .64 Hereditary | 11.7 | 9.9 | 1.57 Not hereditary | 3.5 | 3.2 | .29 ----------------------------------------------------- 4. Idiocy and Imbecility| 14.4 | 12.8 | 1.58 Hereditary | 21.6 | 19.3 | 2.12 Not hereditary | 11.5 | 10.2 | 1.37 ----------------------------------------------------- [A] Per thousand. [Footnote 73: Feer, op. cit., pp. 13-14.]