A Class-Struggle, therefore a struggle of class against class; and a struggle (this is understood), by the methods of which I will soon speak in discussing the four modes of social transformation: evolution--revolution--rebellion--individual violence. But a Class-Struggle in the Darwinian sense, which renews in the history of Man the magnificent drama of the struggle for life between species, instead of degrading us to the savage and meaningless brute strife of individual with individual. We can stop here. The examination of the relations between Darwinism and socialism might lead us much further, but it would go on constantly eliminating the pretended contradiction between the two currents of modern scientific thought, and it would, on the contrary, confirm the essential, natural and indissoluble harmony that there is between them. Thus the penetrating view of Virchow is confirmed by that of Leopold Jacoby. "The same year in which appeared Darwin's book (1859) and coming from a quite different direction, an identical impulse was given to a very important development of social science by a work which long passed unnoticed, and which bore the title: _Critique de l'economie politique_ by KARL MARX--it was the forerunner of _Capital_. "What Darwin's book on the _Origin of Species_ is on the subject of the genesis and evolution of organic life from non-sentient nature up to Man, the work of Marx is on the subject of the genesis and evolution of association among human beings, of States and the social forms of humanity."[42] And this is why Germany, which has been the most fruitful field for the development of the Darwinian theories, is also the most fruitful field for the intelligent, systematic propaganda of socialist ideas. And it is precisely for this reason that in Berlin, in the windows of the book-stores of the socialist propaganda, the works of Charles Darwin occupy the place of honor beside those of Karl Marx.[43] FOOTNOTES: [37] LARFARGUE, _Le Materialisme economique_, in _Ere nouvelle_, 1893. [38] Avoiding both of the mutually exclusive theses that civilization is a consequence of race or a product of the environment, I have always maintained--by my theory of the natural factors in criminality--that it is the resultant of the combined action of the race and the environment. Among the recent works which support the thesis of the exclusive or predominant influence of race, I must mention LE BON, _Les lois psychologiques de l'evolution des peuples_, Paris, 1894. This work is, however, very superficial. I refer the reader for a more thorough examination of these two theses to Chap. IV of my book _Omicidio nell' anthropologia criminale_, Turin, 1894.