Column 4:  Self-fertilised Plants (self-fertilised for five generations).

Pot 1 :  64 5/8 :  57 2/8 :  43 6/8. 
Pot 1 :  24 :  64 :  56 3/8. 
Pot 1 :  51 4/8 :  58 6/8 :  31 5/8.

Pot 2 :  48 7/8 :  59 7/8 :  41 5/8. 
Pot 2 :  54 4/8 :  58 2/8 :  41 2/8. 
Pot 2 :  58 1/8 :  53 :  18 2/8.

Pot 3 :  62 :  52 2/8 :  46 6/8. 
Pot 3 :  53 2/8 :  54 6/8 :  45. 
Pot 3 :  62 7/8 :  61 6/8 :  19 4/8.

Pot 4 :  44 4/8 :  58 7/8 :  37 5/8. 
Pot 4 :  49 2/8 :  65 2/8 :  33 2/8. 
Pot 4 :  .. :  59 6/8 :  32 2/8.

Pot 5 :  43 1/8 :  35 6/8 :  41 6/8. 
Pot 5 :  53 7/8 :  34 6/8 :  26 4/8. 
Pot 5 :  53 2/8 :  54 6/8 :  0.

Pot 6 :  37 4/8 :  56 :  46 4/8. 
Pot 6 :  61 :  63 5/8 :  29 6/8. 
Pot 6 :  0 :  57 7/8 :  14 4/8.

Pot 7 :  59 6/8 :  51 :  43. 
Pot 7 :  43 4/8 :  49 6/8 :  12 2/8. 
Pot 7 :  50 5/8 :  0 :  0.

Pot 8 :  37 7/8 :  38 5/8 :  21 6/8. 
Pot 8 :  37 2/8 :  44 5/8 :  14 5/8.

Total :  1051.25 :  1190.50 :  697.88.

The twenty-one Westerham-crossed plants now averaged 50.05 inches; the twenty-two intercrossed plants, 54.11 inches; and the twenty-one self-fertilised plants, 33.23 inches in height.  We thus get the following ratios:—­

The Westerham-crossed plants in height to the self-fertilised as 100 to 66.

The Westerham-crossed plants in height to the intercrossed as 100 to 108.

The intercrossed plants in height to the self-fertilised as 100 to 61.

We here see that the Westerham-crossed (the offspring of plants self-fertilised for four generations and then crossed with a fresh stock) have gained greatly in height, since they were first measured, relatively to the plants self-fertilised for five generations.  They were then as 100 to 91, and now as 100 to 66 in height.  The intercrossed plants (i.e., those which had been intercrossed for the last five generations) likewise exceed in height the self-fertilised plants, as occurred in all the previous generations with the exception of the abnormal plants of the third generation.  On the other hand, the Westerham-crossed plants are exceeded in height by the intercrossed; and this is a surprising fact, judging from most of the other strictly analogous cases.  But as the Westerham-crossed plants were still growing vigorously, while the intercrossed had almost ceased to grow, there can hardly be a doubt that if left to grow for another month they would have beaten the intercrossed in height.  That they were gaining on them is clear, as when measured before they were as 100 to 119, and now as only 100 to 108 in height.  The Westerham-crossed plants had also leaves of a darker green, and looked altogether more vigorous than the intercrossed; and what is much more important, they produced, as we shall presently see, much heavier seed-capsules.  So that in fact the offspring from the self-fertilised plants of the fourth generation crossed by a fresh stock were superior to the intercrossed, as well as to the self-fertilised plants of the fifth generation—­of which latter fact there could not be the least doubt.