of Edinburgh, Session 1864-65. 289 
absolute identity of form, as in crystals, is the result of laws 
which have nothing to do with inheritance, but of forces whose 
nature it is to aggregate the particles of matter in identic shapes. 
It is impossible to say how far a similar unity of effect may have 
been impressed on the forces through which vital organisms are 
first started on their way. There are some essential resemblances 
between all forms of life which it is impossible even in imagina- 
tion to connect with community of blood by descent. For ex- 
ample, the bilateral arrangement is common to all organisms, 
down at least to the Kadiata. Again, the general mechanism 
of the digestive organs by which food is in part assimilated 
and part rejected, is also common through a range of equal ex- 
tent. These are fundamental similarities of plan, depending pro- 
bably on the very nature of forces of which we know nothing, but 
which we have not the slightest reason to suppose are due to in- 
heritance. Other similarities of plan may depend on the same 
laws, equally unconnected with inheritance by descent. Indeed, 
inheritance has been suggested as the cause, mainly because there 
is a difficulty in conceiving any other. But there is at least an 
equal difficulty in conceiving the applicability of this cause to Man. 
Mons. Gruizot, in the work already quoted,* lays it down as a 
physical impossibility that Man — the human pair — can have been 
introduced into the world except in complete stature — in the full 
possession of all his faculties and powers. He holds it as certain 
that on no other condition could Man, on his first appearance, have 
been able to survive and to found the human family. Even those 
who distrust this argument as entitled to the rank of a self-evident 
physical truth, must admit that it is at least quite as good as the 
opposite assertion, that any origin except the origin of natural birth 
is inconceivable. Where our ignorance is so profound no reasoning 
of this kind is of much value ; but there is much to be said in support 
of Mons. Gruizot’s position. Certainly, Man as a mere animal is the 
most helpless of all animals. His whole frame has relation to his 
mind, and apart from that relation, it is feebler than the frame 
of any of the brutes. Yet in its plan and structure it is homo- 
logically, that is ideally, the same as theirs — organ answering 
^ Meditations sur I’Esseuce de la Religion Chretienne, p. 22. 
