32 SOCIAL SCIENTIST provide the basis for the strategy and tactics of the working class movement in the coming years of struggle. This was a matter of considerable interest to both Marx and Engcls. Both sent detailed replies with Engels producing a short critical appreciation.5 Marx and Engels both report the "excitement" with which they read the play. Their replies, though critical, are precisely the kind of replies expected of serious and interested readers, deeply engaged in such problems. The play reached Marx and Engels at an opportune moment. Marx had been reading aesthetics evidently because he had been asked to write an article on the subject for Charles Dana's New American Encyclopaedia, and Lifschitz reminds us that he had excerpted a comment by the philosopher Vischer: "The proper theme for a tragedy is revolution."6 Lasalle. with his claim to have written the tragedy of revolution as such, was thus working in an area of common interest. Engels's interest in the subject stemmed from the fact that he too had made a serious study of the peasant wars of sixteenth century Germany, which was published in 1850. There Engels had drawn co'nclusions necessitating an understanding of the reasons for the failure of the revolution of 1848. All the more Engels was interested in Lasalle's studies because the latter was still a potential ally in the forthcoming political struggles in Germany at that time. Since the crisis of 1857, partly due to the Crimean war, the question regarding the theory and practice of working class struggles had once again become important.7 Lasalle was known as a competent organizer and Marx and Engels apparently included him in the "party of the proletariat." This explains the comradely tone of the replies of Marx and Engels to Lasalle without compromising on the principled criticism. This is evident in Engels's letter to Lasalle: You see that I make very high, that is to say, the very highest demands on your work both from the aesthetic and historical points of view, and the fact that I must do this to be able to make an objection here and there will be for you the best proof of my approval. Among us, criticism, in the interests of the Party itself, has for years been of necessity as open as possible; in general, however, I and all of us are always pleased when there is new proof that our Party, in whatever area it appears, always performs with superiority. And that you have done in this case too.8 Both Marx and Engels drew attention to formal deficiencies without being pedantic. Marx felt that since Lasalle had written