Herr Duehring is on his guard against entering upon the positive side of this question. Instead he must again find fault with the struggle for existence. There can be no argument about a struggle for existence between plants and the genial eaters of plants "in a sufficiently accurate sense the struggle for existence only occurs within the sphere of brutality, in so far as nourishment depends upon robbery and consumption." And after he has reduced the concept struggle for existence to these narrow limits he gives his wrath free play as regards the brutality of this conception which he himself has narrowed down to a brutal conception. But this moral wrath simply reacts on Herr Duehring himself, the inventor of this sort of struggle for existence. It is not Darwin therefore who seeks among the lower animals the "conditions of the operations of nature" (as a matter of fact Darwin would have included the whole of organic nature in the struggle), but one of Herr Duehring's bugaboos. The expression "struggle for existence" in particular excites Herr Duehring's lofty moral scorn. That this actually exists among plants every meadow, every cornfield and every wood can show him. We need not trouble about the name, whether one call it "struggle for existence" or "lack of the conditions of existence and want of mechanical realisation," but as to how this fact operates as regards the maintenance or transformation of species. With regard to this Herr Duehring persists in a characteristically stubborn silence. We cannot trouble ourselves any more about natural selection. But "Darwinism produces its changes and differentiations out of nothing." Darwin thoroughly understands that he is engaged with the causes which have produced changes in individuals and in the second place he is engaged with the mode in which such individual differentiations tend to mark off a race, a genus, or a species. Darwin moreover was less occupied in discovering these causes, which up to the present are either entirely unknown or on which there is only general information, than in discovering a rational form in which to establish their reality, to embrace their permanent significance. But Darwin ascribed too wide a reach to his discovery in this that he made it an exclusive means of variation in species and neglected the causes of individual differentiations from the general form. This mistake however is common to most people who make a step forwards. Next, if Darwin produces his changes in individual types out of nothing and thereby excludes the wisdom of the breeder, the breeder on his part must not only display his wisdom but he must produce out of nothing real changes in plant and animal forms. But who has given the impetus to the investigation as to whence these variations and differentiations proceed? It is again no one but Darwin.