128/354 I left out this and many other subjects, which I now see ought to have been introduced. I have inserted a discussion on this subject in the foreign editions. In the third Edition a discussion on this point is added in Chapter IV.) In no case will any organic being tend to retrograde, unless such retrogradation be an advantage to its varying offspring; and it is difficult to see how going back to the structure of the unknown supposed original protozoon could ever be an advantage. |