126 FOOT-NOTES TO EVOLUTION. 
mother, not his grandfather or grandmother, nor yet, 
the whole human race, in one of the chains of which he 
forms a single link. When a son inherits his maternal 
grandfather’s beard it is really his mother’s beard which 
he acquires. It is the beard which his mother would 
have had had she been a man, 
Dr. Brooks says: “ When the son of a beardless boy 
grows up and acquires a beard, we may be permitted to 
say that he has inherited his grandfather’s beard; but 
this is only a figure of speech, and he actually inherits 
the beard his father might have acquired had he lived; 
nor would the case of a child descended from a series of 
ten or a hundred beardless boys be any different.” * 
The species and race characters being the same for 
father and mother, must be the same for the son. They 
have to be subtracted from each of them. For it is evident that 
the inheritance from the grandparents and from far-off ancestors 
came through the parents. If not active in them, these qualities 
must have been latent, and in either case they came from them 
to Richard Roe. In strictness the inheritance of C, D, E, etc., 
is included in B, as are also the race qualities and the qualities 
of the species. 
* Setting aside these considerations, it is evident that, as A + B, 
A+B’,A+C,A+D’, etc., represent each a distinct personality, 
Richard Roe from the first will differ notably from A + B, as- 
sumed as the original formula of his father. To what extent 
this difference goes depends on the value of A as compared with 
B, B’, etc. ; in other words, on the uniformity of the pedigree. 
If B, C, D and the rest were very closely alike, as is the case 
with ‘‘thoroughbreds,” the differential elements will be small, 
and the complete Richard Roe will be very like the rest of them. 
If B, C, D are small quantities, and A + B essentially similar to 
A +D, the addition of will count for but little in the ag- 
Cc 
weétn 
gregate. To be thoroughbred is to be bred so as to exclude indi- 
vidual variation. It tends to prevent failures or deficiencies, and 
at the same time it tends to limit advance, 
