THE HEREDITY OF RICHARD ROE. 125 
Out of these elements Mr. Galton frames the idea of a 
“ mid-parent,” a sort of centre of gravity of heredity, 
which in language, not algebra, would 
represent the same set of ideas. But, as 
Dr. Brooks has observed, “It may be well to ask what 
evidence there is that the child does inherit from any 
ancestor except its parents, for descent from a long line 
of ancestors is not necessarily equivalent to inheritance 
from them, and it is quite possible that the conception 
of a ‘mid-parent’ may be nothing but a logical abstrac- 
tion.” * The parents of Richard Roe were his father and 
The mid-parent. 
fact. In each process of generation, half these qualities, al- 
ready once divided, are lost or rendered unrecognisable by indi- 
vidual variations or by contradictory blendings. To each parent 
Galton assigns about twenty-five per cent of these personal 
B, B’ 
qualities. Accepting this as approximate, a + Fc be nearer 
the actual fact, and we may so take it. But the latent influence 
of the grandparents must come in, these represented by C, C’, C”, 
and C’" respectively. In this case the divisor may apparently 
be 16, which corresponds to Galton’s estimate of 63 per cent. 
Should we wish to go farther back, the influence of the great- 
grandparents, D, D’ D”, etc., eight of them, could be added, each 
with 64 as its divisor. 
It is evident that these divisors are all proximate only, and 
varying at each cleavage of the germinal chromatin. The un- 
known and fluctuating element in this division we may designate 
would represent the direct heritage of his 
B’. Cc Cc 
nt 36 +n? 
B 
as + 7. a 
B 
father to Richard Roe. ThenA ta a E ers z 
Cc" Cc” | 8Detc. 16 Eete. 
1 + 16 +n? 6442 + 356 +n" 
draft of the hereditary framework of Richard Roe. 
' In that case the formula given in the above note would be 
modified to this extent. The value of C, D, E, etc., would be 
limited to the hereditary characters latent but undeveloped in B, 
etc. Their value would be less than B, for some part of B would 
etc., will be our first rough 
