Till 1858 Lassalle resided mostly in the Rhine country, prosecuting the suit of his friend the countess, and afterwards completing his work on Heracleitus, which was published in that year. He was not allowed to live in Berlin because of his connection with the disturbances of 1848. In 1859 he returned to the capital disguised as a carter, and finally, through the influence of Humboldt with the king, received permission to remain. In the same year he published a remarkable pamphlet on _The Italian War and the Mission of Prussia_, in which he came forward to warn his countrymen against going to the rescue of Austria in her war with France. He argued that if France drove Austria out of Italy she might annex Savoy, but could not prevent the restoration of Italian unity under Victor Emmanuel. France was doing the work of Germany by weakening Austria, the great cause of German disunion and weakness; Prussia should form an alliance with France in order to drive out Austria and make herself supreme in Germany. After their realisation by Bismarck, these ideas have become sufficiently commonplace; but they were nowise obvious when thus published by Lassalle. In this, as in other matters, he showed that he possessed both the insight and foresight of a statesman. In the course of the Hatzfeldt suit Lassalle had acquired no little knowledge of law, which proved serviceable to him in the great work, _System of Acquired Rights_, published in 1861. The book professes to be, and in a great measure is, an application of the historical method to legal ideas and institutions; but it is largely dominated also by abstract conceptions, which are not really drawn from history, but read into it. The results of his investigation are sufficiently revolutionary; in the legal sphere they go even farther than his socialistic writings in the economic and political. But with one important exception he made no attempt to base his socialistic agitation on his _System of Acquired Rights_; it simply remained a learned work. Hitherto Lassalle had been known only as the author of two learned works, and as connected with one of the most extraordinary lawsuits of the nineteenth century, which had become a widespread scandal. Now began the brief activity which was to give him an historical significance. His revolutionary activity in 1848, though only a short phase in his career, was not an accident; it represented a permanent feature of his character. In him the student and the man of action were combined in a notable manner, but the craving for effective action was eminently strong. The revolutionary and the active elements in his strangely mixed nature had for want of an opportunity been for many years in abeyance.