SOCIAL SCIENTIST henceforth no longer form for us a mass of practical judgments for or against which we should take sides in each contingency. The political parties which since the International have established themselves in different countries, in the name of the proletariat, and taking it clearly for their base, have felt, and feel, in proportion as they are born and develop, the imperious necessity of adopting and conforming their programme and their action to circumstances always different and multiform. But not one of these parties feels the dictatorship of the proletariat so near that it experiences the need or desire or even the temptation to examine anew and pass judgment upon the measures proposed in the Manifesto. There are really no historic experiences but those that history makes itself. It is as impossible to foresee them as to plan them beforehand or make them to order. That is what happened at the moment of the Commune, which was and which still remains up to this day the only experience (although partial and confused because it was sudden and of short duration) of the action of the proletariat in gaining control of political power. This experience, too, was neither desired nor sought for, but imposed by circumstances. It was heroically carried through and it has become a salutary lesson for us to-day. It might easily happen that where the socialist movement is still in its beginnings, appeal may be made, for lack of personal direct experience - as often happens in Italy - to the authority of a text from the Manifesto as if it were a precept, but these passages are in reality of no importance. Again, we must not, as I believe, seek for this vital part, this essence, this distinctive character, in what the Manifesto says of the other forms of socialism of which it speaks under the name of literature. The entire third chapter may doubtless serve for defining clearly by way of exclusion and antithesis, by brief but vigorous characterizations, the differences which really exist between the communism commonly characterized to-day as scientific, - an expression sometimes used in a mistaken and contradictory way, -that is to say, between the communism which has the proletariat for its subject and the proletarian revolution for its theme, and the other forms of socialism; reactionary, bourgeois, semi-bourgeois, petit-bourgeois, Utopian, etc. All these forms except one1 have re-appeared and renewed themselves more than once. They are reappearing under a new form even to-day in the countries where the modern proletarian movement is of recent birth. For these countries and under these circumstances the Manifesto has exercised and still exercises the function of contemporary criticism and of a literary whip. And in the