Page:Darwinism by Alfred Wallace 1889.djvu/85

III virginianus are registered, we see a remarkable spreading out of the spots, showing in some of the characters a tendency to segregation into two or more groups of individuals, each varying considerably from the mean.



In order fully to appreciate the teaching of these diagrams, we must remember, that, whatever kind and amount of variations are exhibited by the few specimens here compared, would be greatly extended and brought into symmetrical form if large numbers—thousands or millions—were subjected to the same process of measurement and registration. We know, from the general law which governs variations from a mean value, that with increasing numbers the range