Between the years 1843 and 1844 we have the second and probably the most important critical period in the intellectual development of Marx. In 1837 he had become a disciple of Hegel, into whose philosophy he penetrated deeper and deeper during the two years which ensued. Between 1843 and 1844 he became a Socialist, and in the following two years he laid the foundations of those social and historical doctrines associated with his name. Of the way he came to be a Socialist and by what studies he was led to Socialism, we know nothing. All that can be said is that in the summer of 1848 he must have pursued the reading of French Socialist literature just as assiduously as he did the study of Hegel in 1837. In his letters to Arnold Ruge, written about 1843, and printed in the Franco-German Year Books, we find a few passages which bear witness to his sudden turnover. In a letter from Cologne (May, 1843) he remarks: "This system of acquisition and commercialism, of possession and of the exploitation of mankind, is leading even more swiftly than the increase of population to a breach within the present society, which the old system cannot heal, because indeed it has not the power either to heal or create, but only to exist and enjoy." That is still in the sentimental vein, and anything but dialectical criticism. In the following few months, however, he made surprisingly rapid progress towards the fundamental ideas of that conception of history and society, which later on came to be known as Marxism, and which he almost built up into a complete system during those restless years of exuberant creative activity, 1845-46. In a letter from Kreuznach, dated September, 1843, he shows already an acquaintance with Fourier, Proudhon, Cabet, Weitling, etc., and sees his task not in the setting up of Utopias but in the criticism of political and social conditions, "in interpreting the struggles and aspirations of the age." And by the winter of 1843 he has already advanced so much as to be able to write the introduction to the criticism of Hegel's "Philosophy of Law," which is one of the boldest and most brilliant of his essays. He deals with the question of a German revolution, and asks which is the class that could bring about the liberation of Germany. His answer is that the positive conditions for the German revolution and liberation are to be sought "in the formation of a class in chains, a class which finds itself in bourgeois society, but which is not of it, of an order which shall break up all orders. The product of this dissolution of society reduced to a special order is the proletariat. The proletariat arises in Germany only with the beginning of the industrial movement; for it is not poverty resulting from natural circumstances but poverty artificially created, not the masses who are held down by the weight of the social system but the multitude arising from the acute break-up of society--especially of