20 FINGER PRINTS
CHAP.
patterns are apparently the only peculiarity in which Panmixia, or the effect of promiscuous marriages, admits of being studied on a large scale. The result of Panmixia in finger markings, corroborates the arguments I have used in Natural Inheritance and elsewhere, to show that " organic stability " is the primary factor by which the distinctions between genera are maintained ; consequently, the progress of evolution is not a smooth and uniform progression, but one that proceeds by jerks, through successive " sports " (as they are called), some of them implying considerable organic changes, and each in its turn being favoured by Natural Selection.
The same word " variation " has been indiscriminately applied to two very different conceptions, which ought to be clearly distinguished ; the one is that of the " sports " just alluded to, which are changes in the position of organic stability, and may, through the aid of Natural Selection, become fresh steps in the onward course of evolution ; the other is that of the Variations proper, which are merely strained conditions of a stable form of organisation, and not in any way an overthrow of them. Sports do not blend freely together ; variations proper do so. Natural Selection acts upon variations proper, just as it does upon sports, by preserving the ,best to become parents, and eliminating the worst, but its action upon mere variations can, as I conceive, be of no permanent value to evolution, because there is a constant tendency in the offspring to " regress " towards the parental type. The amount and results
