In Table 2/17, we see the average or mean heights of the ten successive generations of the intercrossed and self-fertilised plants, grown in competition with each other; and in the right hand column we have the ratios of the one to the other, the height of the intercrossed plants being taken at 100. In the bottom line the mean height of the seventy-three intercrossed plants is shown to be 85.84 inches, and that of the seventy-three self-fertilised plants 66.02 inches, or as 100 to 77. TABLE 2/17. Ipomoea purpurea. Summary of measurements of the ten generations. Heights of Plants in inches: Column 1: Name of Generation. Column 2: Number of Crossed Plants. Column 3: Average Height of Crossed Plants. Column 4: Number of Self-fertilised Plants. Column 5: Average Height of Self-fertilised Plants. Column 6: n in Ratio between Average Heights of Crossed and Self-fertilised Plants, expressed as 100 to n. First generation Table 2/1 : 6 : 86.00 : 6 : 65.66 : 76. Second generation Table 2/2 : 6 : 84.16 : 6 : 66.33 : 79. Third generation Table 2/3 : 6 : 77.41 : 6 : 52.83 : 68. Fourth generation Table 2/5 : 7 : 69.78 : 7 : 60.14 : 86. Fifth generation Table 2/6 : 6 : 82.54 : 6 : 62.33 : 75. Sixth generation Table 2/7 : 6 : 87.50 : 6 : 63.16 : 72. Seventh generation Table 2/8 : 9 : 83.94 : 9 : 68.25 : 81. Eighth generation Table 2/9 : 8 : 113.25 : 8 : 96.65 : 85. Ninth generation Table 2/10 : 14 : 81.39 : 14 : 64.07 : 79. Tenth generation Table 2/11 : 5 : 93.70 : 5 : 50.40 : 54. All ten generations together : 73 : 85.84 : 73 : 66.02 : 77. (DIAGRAM 2/1. Diagram showing the mean heights of the crossed and self-fertilised plants of Ipomoea purpurea in the ten generations; the mean height of the crossed plants being taken as 100. On the right hand, the mean heights of the crossed and self-fertilised plants of all the generations taken together are shown (as eleven pairs of unequal vertical lines.)) The mean height of the self-fertilised plants in each of the ten generations is also shown in the diagram 2/1, that of the intercrossed plants being taken at 100, and on the right side we see the relative heights of the seventy-three intercrossed plants, and of the seventy-three self-fertilised plants. The difference in height between the crossed and self-fertilised plants will perhaps be best appreciated by an illustration: If all the men in a country were on an average 6 feet high, and there were some families which had been long and closely interbred, these would be almost dwarfs, their average height during ten generations being only 4 feet 8 1/4 inches.