1892.] The Difficulties in the Heredity Theory. 545 
study of man, and he supported the idea of continuity in the 
germ-cells in order to account for the law of transmission 
of “latent” characters; it is evident from this law that only 
a part of the organic units of the “stirp ” become “ patent” in 
the individual body; some are retained latent in the germ- 
cells, and become patent only in the next or some succeeding 
generation. For example, the genius for natural science was 
“patent” in Erasmus Darwin, grandfather of the great natur- 
alist, it was “latent” in his son, and reappeared intensified in 
his grandson, Charles Darwin. I have elsewhere’ summed up 
as follows Galton’s general results, which so remarkably 
strengthen the “continuity” idea: We are made up, bit by 
bit, of inherited structures, like a new building, composed of 
fragments of an old one, one element from this progenitor, 
another from that, although such elements are usually trans- 
mitted in groups. The hereditary congenital constitution 
thus made up is far stronger than the influences of environ- 
ment and habit upon it. A large portion of our heritage is 
unused, for we transmit peculiarities we ourselves do not 
exhibit. The contributions from each ancestor can be 
estimated in numerical proportions, which have been exactly 
determined, from statistics of stature in the English race; 
thus the contributions from the “patent” stature of the two 
parents together constitute one-half; while the contributions 
by “latent” heritage from the grandparents constitute one- 
sixteenth, ete. One of the most important demonstrations by 
Galton, is the law of regression ; this is the factor of stability in 
race type which acts as gravitation does upon the pendulum; 
if an individual or a family swing far from the average char- 
acteristics of their race, and display exceptional physical or 
mental qualities, the principle of regression in heredity tends 
to draw their offspring back to the average. 
Now how shall we distinguish regression from reversion? 
Very clearly, I think; regression is the short pull which tends 
to draw every variation and the individual as a whole back 
to the contemporary typical form, while reversion is the long 
pull which draws the typical form of one generation back to 
Atlantic Monthly, March, 1891, p. 359.. 
