Dr. Corrigan continued for some years zealously to investigate the functions of the heart, and he experimented largely upon the hearts of fishes and reptiles. He published an important paper “On the Motions and Sounds of the Heart,” in the _Dublin Medical Transactions_, 1830, part i. At this period of his career, when practice as yet was but scanty, he was much encouraged by reading “The Lives of British Physicians, from Linacre to Gooch,” published in 1830, and he referred to it afterwards as showing that “there is but one road to excellence and success in our profession, and that is by steady study and hard labour; and you will at least always have this consolation in your dreariest hour of labour, that no proud man’s contumely, no insolence of office, nor ‘spurns that patient merit of the unworthy takes,’ can bar your way.” Resigning his post at the Meath Street Dispensary, Corrigan became successively attached to the Cork Street Fever Hospital, and to the Jervis Street Hospital. Yet the Irish College of Physicians failed to discern his great merits, and blackballed him when he was first proposed for the fellowship, a mistake which they subsequently atoned for in some measure by electing him their president for five successive years, and by commissioning a statue of him, by Foley, at the conclusion of his term of office. In 1833 he began to lecture on the practice of medicine in the Carmichael School of Medicine, and practice grew rapidly. In 1840 he was appointed physician to the House of Industry Hospitals, which post he held till 1866. Here he delivered a noteworthy course of lectures on the Nature and Treatment of Fever, which were published in 1853. He accepted and enforced the modern views as to the distinctness of typhoid from typhus fever. In 1841 Dr. Corrigan became a member of the Senate of the new Queen’s University, of which after thirty years he was appointed Vice-Chancellor. In 1849 Dublin University gave him the honorary M.D. He was assiduously devoted to the onerous duties of a Commissionership of National Education. As to practice, he became the most popular and highly remunerated physician Dublin had ever seen, having for many years more calls upon him than he could possibly attend to, and receiving in several years as much as £9000 per annum in fees. In 1866 he was made a baronet in consideration both of his medical position and of his important services to national education. He was also Physician-in-Ordinary to the Queen in Ireland.