Although new and important modifications may not arise from reversion and analogous variation, such modifications will add to the beautiful and harmonious diversity of nature.
It of course cannot encompass the entirety of that transition, nor can this single organism answer the question of whether cancer is a reversion to single celled life.
Of these latter variations several may be attributed to reversion; and the characters which thus reappear were, it is probable, in many cases at first gained in a gradual manner.
The tendency to reversion may often check or prevent the work; but as this tendency has not prevented man from forming by selection numerous domestic races, why should it prevail against natural selection?
It's this idea that maybe a cancer is kind of its own type of organism, a reversion of sorts to a past that is of course also very much present: the life of single-celled organisms.