In Table 15 have been brought together for comparison the means of the several horizontal rows of Tables 1 to 13. By examining the vertical columns of Table 15 the mean grade of the offspring of parents of a particular grade in any generation may be compared at a glance with that of parents of the same grade in any other generation. By running the eye down the columns, it will be observed that the mean grade of the offspring tends to increase upon repeated selection. Thus parents of grade 3.75 appear first in generation 4, the grade of their offspring being 2.75; the offspring of such parents in subsequent generations grade in order, 3.07, 3.22, 3.35, 3.49, 3.50, 3.69, 3.75, and 3.83 (twelfth generation not complete). The difference between parents and offspring in this series grows less and less and finally disappears altogether. If the grade of 3.75 parents in this series is compared with the grade of _all_ offspring in the corresponding generations we have the following: TABLE A. +-----------+-----------------------+------------------------+ |Generation.| Mean of offspring of | Mean of offspring of | | | 3.75 parents. | all parents. | +-----------+-----------------------+------------------------+ | 4 | 2.75 | 2.73 | | 5 | 3.07 | 2.90 | | 6 | 3.22 | 3.11 | | 7 | 3.35 | 3.20 | | 8 | 3.49 | 3.48 | | 9 | 3.50 | 3.54 | | 10 | 3.69 | 3.73 | | 11 | 3.75 | 3.77 | | 12 | 3.83 (35 individuals)| 3.94 (590 individuals)| +-----------+-----------------------+------------------------+ In generation 4 the 3.75 parents represented the most advanced individuals of the series, a whole grade in advance of the general average of the race. Their offspring showed a correspondingly large regression. The general average of the race steadily advanced in later generations until in generation 11 it equaled that of the 3.75 parents; then the regression vanished. In the following generation, 12 (which is still incomplete, but in which the average of the offspring thus far is 3.94), the 3.75 group of parents, which are now _below_ the average of the race, actually produce offspring of higher grade than themselves, viz, 3.83. It will thus be seen that the _regression is uniformly toward the mean of the race and changes its direction when that mean changes its position with reference to a particular grade of parents_. This conclusion is supported by other columns of Table 15, but is best illustrated by this particular case because here the selection has extended over a greater number of generations than elsewhere in the series.