DESCENT WITH MODIFICATION 163 
The exceptional offspring and his parent. A glance at the table 
on page 156 will show another great principle in transmission, 
namely, that a given class of offspring may be produced in vari- 
ous ways. For example, the heights of offspring as recorded in 
column 13 are clearly exceptional. These people are over six feet 
tall, but they were produced byall sorts of parents from 72.5 inches 
down to 65,5. While the parents were thus distributed, yet the 
greatest wzmbcr of exceptional people (11) came from mediocre 
parentage, but the greatest proportion of tall people came from 
extremely tall parentage. Thus the 11 of this column were the 
product of 183 families (see column 16), while as many as 7 
were produced by 19 midparents that were three inches taller, 
— another evidence of regression and of progression as well. 
Reversion. When we see how many tall people beget short 
children and how many tall children come of short parents (see 
rows / and & in the table), we are not surprised that occasion- 
ally an unaccountable case will turn up, as when a red-headed 
boy is born of black-haired parents, and nobody can remember 
even a red-headed grandparent. Aye, remember; there’s the 
trouble. The total ancestry runs back for many generations and 
we remember but a few, — rarely back of the grandparent, — 
whereas each of us has over two thousand ancestors within ten 
generations. In the case of the red-headed boy some one of them 
was in all likelihood red-headed, and this that has turned up is 
a ‘reversion’ to that ancestor ; for cvery individual transniits 
all the characters of his ancestry, and anything that is trans- 
mitted may at any time become dominant and then visible. 
That is about all there is of the matter of reversion or throw- 
ing back, about which such a “to do” has been made. As a 
physiological fact it is interesting; as a matter in plant or 
animal improvement it hardly applies, for as soon as systematic 
selection is a little while practiced, the chance of reversion 
rapidly reduces to practically nothing. 
Degeneracy. This is a matter of importance in human affairs 
rather than in those of the animal and plant, but facts such as 
