This work, commenced in Hamburg, Delmedigo could not finish there. A pestilence broke out, and drove him, physician though he was, to Glückstadt. In this small community, where, as he said, there was neither town (Stadt) nor luck (Glück), he could find no means of subsistence, and he traveled on to Amsterdam about 1629. He could not attempt to practice medicine in a city where physicians lived of even higher eminence than at Hamburg, and so was obliged a second time to apply himself to the functions of rabbi. To show his importance, he printed his scientific replies to the questions of his Polish admirers, with the fulsome eulogies, clouds of incense, and foolish homage which the young Karaite Serach had offered him. It is a work of truly Polish disorder, in which mathematical theorems and scientific problems are discussed by the side of philosophical and theological questions, in a confused way. Delmedigo took care not to print his attacks upon the Kabbala and the Talmud, and his preference for the Karaites--in short, all that he had written to please the rich Serach. Instead of publishing an encyclopædic work which he boastfully said he had composed in his earliest youth, and which embraced all sciences and solved all questions, he produced a mere medley. The Amsterdam community was then full of suspicion against philosophy and culture owing to the reckless behavior of Da Costa, and therefore Delmedigo thought it advisable to ward off every suspicion of unbelief, and get a reputation for strictest orthodoxy. This transparent hypocrisy did not answer well. He was, it is true, appointed preacher, and partially rabbi, in or near Amsterdam, but he could remain in Holland only a few years. Poor and unstable as he was, he went with his wife to Frankfort-on-the-Main about 1630 to seek means of subsistence. But here, in a German community, where Rabbinical learning was diffused, he could not obtain a rabbinical office; but he could turn his medical knowledge, scanty as it was, to account. As he felt no vocation for the office of rabbi, nor for medical practice, it was a matter of indifference if he changed the preacher's gown for the doctor's mantle. He was engaged, under irksome conditions, as communal doctor (February 14, 1631). How long he remained at Frankfort is not known; his position cannot have been favorable, for he removed to Prague (about 1648-1650), and in this most neglected community he settled. Later (1652) he was at Worms, probably only temporarily, and ended his life, which had promised so much, and realized so little, at Prague. Nor did he publish any part of his great work, which he had announced with so much pomposity.