The proportions of a typical loop on the thumb are easily ascertained if we may assume that the most frequent values of its variable elements, taken separately, are the same as those that enter into the most frequent combination of the elements taken collectively. This would necessarily be true if the variability of each element separately, and that of the sum of them in combination, were all strictly normal, but as they are only quasi-normal, the assumption must be tested. I have done so by making the comparisons (_A_) and (_B_) shown in Table XXXIV., which come out correctly to within the first decimal place. TABLE XXXIV. +------------------------------------------------------+ | |Right | Left | | |Thumb.|Thumb.| |----------------------------------------|------|------| |(_a_) Median of all the values of KL | 12.5 | 10.1 | |(_b_) Median of all the values of NB | 10.1 | 8.9 | | |------|------| |(_A_) Value of _a/b_ | 1.24| 1.11| |(_A_) Median of all the fractions KL/NB| 1.15| 1.10| |========================================|======|======| |(_c_) Median of all the values of AN | 4.6 | 4.6 | |(_d_) Median of all the values of AH | 4.4 | 3.3 | | |------|------| |(_B_) Value of _c/d_ | 1.05| 1.40| |(_B_) Median of all the fractions AN/AH| 1.08| 1.36| +------------------------------------------------------+ It has been shown that the patterns are hereditary, and we have seen that they are uncorrelated with race or temperament or any other noticeable peculiarity, inasmuch as groups of very different classes are alike in their finger marks. They cannot exercise the slightest influence on marriage selection, the very existence both of the ridges and of the patterns having been almost overlooked; they are too small to attract attention, or to be thought worthy of notice. We therefore possess a perfect instance of promiscuity in marriage, or, as it is now called, panmixia, in respect to these patterns. We might consequently have expected them to be hybridised. But that is not the case; they _refuse to blend_. Their classes are as clearly separated as those of any of the genera of plants and animals. They keep pure and distinct, as if they had severally descended from a thorough-bred ancestry, each in respect to its own peculiar character.