When, not long subsequently, another epidemic of cholera occurred in New York, and a number of cases of the disease were transferred to Hart's Island and there quarantined, volunteers for their medical attendance were asked from among the members of the medical staff of the Charity Hospital. Dr. O'Dwyer was one of the first to come forward and offer his services. Again he contracted the disease, but recovered from it as completely as from typhus. Years afterward he described to a friend his feelings as he lay in one of the hospital tents, the only accommodation that could be provided for him owing to the crowded condition of the wards. His attack was rather severe and yet left him his consciousness, while as he lay expecting death at almost any moment, the thought (as he was wont to relate) sometimes came to him that it was perhaps foolish of him to have volunteered in so dangerous a service. This thought was always put away, however, and he assured his friend that at no time had he ever regretted his exposure to the disease in the cause of suffering humanity. The risks that usually come with professional obligations (it appeared to him) are not to be avoided at the cost of the consciousness of a duty refused. During his service at the Charity Hospital, Dr. O'Dwyer endeared himself to all those with whom he came in contact. In examination for the position of resident on the Island he had passed first, and during his service there it was generally conceded that he towered above his companions in his efficiency and attention to duty. Some of {328} those who were residents with him afterward made names that are distinguished in the history of the practice of medicine in New York City, yet all of them were ever ready to acknowledge that O'Dwyer had been a leader among them in the service. With a very practical turn of mind, he united the capacity for patient work that enabled him to master difficulties, while his devotion to his profession gave him a deep interest in every department of medicine. The foundation of his future success as a practitioner of medicine was laid in these fruitful years of hard work among the poor charity patients of New York City, for whose welfare, as is evident from what we have said, he was ready to make any sacrifice. After about two years of service on Blackwell's Island, Dr. O'Dwyer, who had attracted no little attention by his faithful fulfilment of duty, was appointed examiner of patients--applicants for admission to the hospitals under the control of the City Board of Charities and Correction. He therefore resigned his position on the Island, and in partnership with Dr. Warren Schoonover opened an office on Second Avenue, between Fifty-seventh and Fifty-eighth Streets. With his colleague, he devoted himself especially to obstetrical practice, in which he had great success, delivering in one year, it is said, over three thousand patients.