MEMOIR. — li 
I grant that not one of these reasons has a leg to stand upon in a strictly 
scientific point of view. They are a string of hypotheses, and, further, there 
are some seemingly opposed facts. (1) Hereditary diseases may have been 
originally induced by local causes ; though I think they may be explained 
without. It is said that a peculiar form of teeth becomes hereditary in 
syphilitic families, but I suspect that this could not be perpetuated ; it could 
only be propagated by intermarriage of children of syphilitic parents, which 
would surely die out. Then, too, I have heard that Dr. Brown-Sequard has 
induced epilepsy in rabbits, and this has happened in the brood; if really so, 
this is a strong point; but here again any attempt to perpetuate the brood 
of epileptics must end in extinction. All these are cases of induced dzseases 
of the individual being propagated—could induced innocuous peculiarities be 
so propagated? Englishmen show no tendency to beardless faces after four 
generations of shaving, and a thousand similar instances may be quoted. 
The oldest custom of all, circumcision, has had no effect on the organ of the 
tace, after hundreds of generations, which I have always regarded as a most 
wonderful fact. Again, though the habit of inducing varieties in plants and 
animals has gone on from time immemorial, no one has ever supposed that 
one place is better than another, causing the jirst brood to vary. Whoever 
plants most gets most varieties, z.e., secures most new sorts by after 
selection. To put the question in its simplest form: No one ever supposed 
that of twelve peas in one pod, six grown in England would be more different 
enter se, or from their parents, than the other six grown in Australia. Again, 
as I have remarked in the introductory essay to Mew Zealand, the 
trueness with which seeds from all parts of the world come up in our gardens 
is astounding. Whoever heard of a new species thus raised by the frst 
sowing. Were it otherwise, did individual seeds come wf differently in 
different localities, you would surely, in extreme cases, have different species 
and different genera coming up at once in our gardens. On the other hand, 
Rivett wheat seed produces Rivett’s in Australia the first year; but whereas 
even Rivett wheat has its varieties, and some of them are more suited to 
Australia than England, after several generations the Rivetts of Australia 
will differ from those of England, but through natural selection. In all these 
considerations we must carefully exclude mere stunting, or the effect of 
overgrowth and undergrowth, which are not variations in the sense I allude 
to, though I confess to my inability to point out any scientific distinction that 
is irrefragable. 
‘‘Now all your apparent exceptions are, I grant, very strong cases at 
first sight, but may all be explained by assuming more time than you do for 
the millions of lost individuals. That ‘species will be constant under one 
set of conditions, and variable under another,’ is quite true; but this is no 
proof that even extreme external physical conditions have acted oz the 
pregnant female so as to have produced greater differences amongst her 
ova, or on the sperm cells of the male previously, to an extent Jerceptible in 
the first brood. 
‘*T have long, on other grounds, denied that tropical heat or light Aroduces 
the bright colouring of plants, or that arctic climates Jroduce woolly 
‘covering. These phenomena are far too partial to be attributed to such 
cosmical phenomena. You say, ‘you are convinced that inorganic con- 
