It is probably of this part of his journey that Harvey writes to Viscount Dorchester, "the miseries of the countries we have passed and the hopes of our good success and such news your Honour hath from better hands. I can only complain that by the way we could scarce see a dog, crow, kite, raven or any other bird, or any thing to anatomise, only some few miserable people, the relics of the war and the plague where famine had made anatomies before I came. It is scarce credible in so rich, populous, and plentiful countries as these were that so much misery and desolation, poverty and famine should in so short a time be, as we have seen. I interprete it well that it will be a great motive for all here to have and procure assurance of settled peace. It is time to leave fighting when there is nothing to eat, nothing to be kept, and nothing to be gotten." The forecast was correct. The Mantuan war was soon afterwards brought to a close by the mediation of Pope Urban VIII. It was one of the minor struggles in which Richelieu's attempts to consolidate the power of his master were counteracted by the combined efforts of Spain and the Empire, for in the end Charles of Nevers was left to enjoy his Duchy of Mantua. The plague, too, was especially virulent in Northern Italy about this time. It was reckoned that above a million died of it in the territories which Lennox and his retinue would have traversed to reach Venice; and 33,000 are said to have died in Verona alone. It was partly for this reason and partly, perhaps, from political motives, that the travellers turned off into Spain instead of visiting Italy, as had been intended. In February, 1632, Sir Thomas Edmonde, writing to Sir Harry Vane, says: "the Duke of Lenox has been made a Grand in Spain;" and it was about this time that the party returned homewards.
Harvey was certainly in England on the 26th of March, 1632, for on that day he drew up a set of rules for the Library of the College of Physicians, towards a site for which he had subscribed £100 on the 22nd of December, 1630. The necessity for a new set of rules to govern the use of the Library seems to have been due to an important bequest of 680 volumes presented by Dr. Holsbosch, a graduate in medicine, and a German who had practised surgery and physic in England for fifty years, though he had not attached himself to the College. The new regulations laid down that the key of the room was to remain in the keeping of the President, whilst the key of the book-cases was kept by the Senior Censor. The Library was to be open on all College days to the Fellows, Candidates, and Licentiates; but no book was to be taken away from the College without leave from the President and Censor and the deposit of a "sufficient caution" for its value. Harvey was also present at a meeting of the College of Physicians on the last day of May, 1632, when he signed a petition to the King, praying him to limit the sale of certain poisons unless the purchaser was willing to give his name.