172 Life and Letters of Francis Galton
germinal 'selection oil the origin of species, ' or his `class representation' on the origin of somatic variations. He did not press it himself to its legitimate conclusions, and probably did not see its full bearings on evolution. His general scheme from 'structureless elements' of parent to those of offspring is as follows
through ' Class Representation'
Structureless afford
Elements of
Parent through ' Class Representation'
afford
What I have termed a `Second Selection' Galton terms `Family Representation,' I think, on the ground that these selections produce the various somatic and emetic differences to be found in the members of the same family'. But it seems to me that it would be best simply to speak of first and second selections instead of `class' and `family' representations. Having put forward this scheme Galton now proceeds to express his grave doubts as to the `adult elements' contributing anything or at least anything substantial to the 'structureless elements' of the offspring. He asserts that where the parents have a patent character that also exists in the latent form, i.e. in their gametic characters,
"I should demur, on precisely the same grounds, to objections based on the transmission of qualities to grandchildren being more frequent through children who possess those qualities than through children who do not; for I maintain that the personal manifestation is, on the
average, though it need not be so in every case, a certain proof of the existence of some latent elements." (p. 399.)
In other words Galton is insisting on the somatic characters being only correlated with, or an index to, the gametic characters, and on the absence of complete association. He states that
"the general and safe conclusion is, that the contribution from the patent elements [somatic characters of parent] is very much less than from the latent elements [gametic characters of parent]." (p. 399.)
And again
"We see that parents are very indirectly and only partially related to their own children, and that there are two lines of connection between them, the one [adult latent elements] of large and the other [adult somatic elements] of small relative importance. The former is a collateral
kinship and very distant, the parent being descended through two stages from a structureless source, and the child (as far as the parent is concerned) through five distinct stages from the same source; the other but unimportant line of connection is direct and connects the child with
the parent through two stages." (p. 400.)
Galton even speaks of the 'structureless elements' that go to form the embryonic elements of the parents as going so far as heredity is concerned to "a nearly sterile destination."
Why did not Galton have the confidence at this time to say wholly sterile destination? I think there is not the least doubt that the l'enfant
11 Of course Galton recognised the biparental contributions and in a second diagram shows the increased complexity.
Embryonic |
which by a Adult |
which by a |
|||
Elements |
development Elements |
Second Selection |
|||
become |
contribute to |
Structureless | |||
~- Elements of | |||||
Latent |
which by a |
Latent |
which by a |
Offspring | |
Elements |
development |
Elements |
Second Selection |
||
in Embryo |
become |
in Adult |
contribute to |