F. Extend this to all animals and plants, and the same thing will hold
good concerning them all. I shall now change the ground and demand
assent to another statement. You know that though the offspring of all
plants and animals is in the main like the parent, yet that in almost
every instance slight deviations occur, and that sometimes there is even
considerable divergence from the parent type. It must also be admitted
that these slight variations are often, or at least sometimes, capable of
being perpetuated by inheritance. Indeed, it is only in consequence of
this fact that our sheep and cattle have been capable of so much
improvement.