expression “_Anni Climacterici_” was also used, but this designation has nothing in common with the modern conception of the climacteric. It was believed that the condition of the body underwent a thorough revolution during these climacteric years, and that a new stage, as it were, of organic life was reached. Heinrich von Rantzau, the astronomic aristocrat and statesman, accordingly defines the climacteric years as “_anni, in quibus ad sequentis temporis constitutionem sese vertat ætas et inflectat_.” Therefore, such years should in themselves harbor dangers for corporeal existence, and offer no favorable prospect for the course of diseases. Two kinds of such climacteric years were distinguished. One kind was brought about by multiplication with the figure 7, and they were called _anni hebdomatici_, or _climacterici (stricte sic dicta)_. Accordingly, these were the years 7, 14, 21, 28, 35, 42, 49, 56, 63. These nine years formed the _climactericus parvus_, whereas the years 77, 84, 91, 98, 105, 112, 119, 126 were called the _climactericus magnus_. A multiplication which extended further, to 171, reached the _climactericus maximus_. The other kind of climacteric years was obtained by multiplication with 9, and such years were called _anni enneatici_, or _decretorii_. These were the years 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108, etc. However, these climacteric years did not all present the same dangers, but the peril inherent in them varied considerably. It was determined by the multiplicator, and here especially the 3 and the 7 played a very fatal rôle. The 21st year of life (3 × 7), and the 27th (3 × 9), were one grade higher in the scale of dangers than those obtained by other multiplicators. Still more dangerous were those years arrived at by ascending in spaces of three hebdomads; therefore, the 21st year of life—_i.e._, the period of three hebdomads—namely, 3 × 7; the 42d year, as a period of 2 × 3 hebdomads—_i.e._, 2 × 21; the 63d year of life, as a period of 3 hebdomads—_i.e._, 3 × 21; 84 = to 4 × 21; 105 = 5 × 21, etc. The 49th year of life and the 56th year of life were said to be still more dangerous than these years obtained from the period of three hebdomads. It is true, the cause of the danger is quite obvious in the case of the 49th year; it was the ominous 7 × 7 which here gave rise to forebodings. And it was not quite comprehensible what caused the bad reputation of innocent 56; Rantzau fails to give us a sufficient explanation.