As soon as Mr. Oudney had settled in Edinburgh he resumed his professional studies, and having completed the _curriculum_, prescribed to those who wish to take the degree of Doctor of Medicine, he obtained that academical rank upon the first of August 1817, his inaugural dissertation being “_De Dysenteria Orientali_,” a subject to which his attention was doubtless directed by having had an opportunity of observing the character and treatment of that disease during the period of his naval practice. He now became a medical practitioner in Edinburgh, and was very careful to observe and record the symptoms and circumstances which, in that capacity, came under his notice. While he was thus employed, he was in the habit of imparting the result of his observations to his medical friends, and among others, to Dr. Abercrombie of this city, who, once and again, in his communications to the “Edinburgh Medical and Surgical Journal,” has mentioned Dr. Oudney with approbation, and incorporated his young friend’s information with that of his own. We likewise observe in the same Journal (for July 1820) a paper by Dr. Oudney, entitled, “Cases of _Ileus_ from a twist of the colon,” and we are assured on the authority of one of the most intimate of his medical friends, that he frequently sent communications to the “London Medical Journal.” At this period he was assiduous in the study of chemistry and natural history. Botany, especially, engaged much of his attention; and, we believe, he was indebted to the late Dr. Scott for much valuable information on this interesting department of physical knowledge. He and Dr. Scott commenced a botanical work on the grasses; he was employed by Dr. Duncan in arranging the plates of a botanical work belonging to the university library; and, we have been told, that at one time he entertained serious thoughts of becoming a lecturer on British botany. We know that he was enthusiastically attached to this study, and oftener than once we have accompanied him when he went on botanical excursions. He not only attended the natural history class in the university of Edinburgh, so ably taught by Professor Jameson, but he became likewise a member of the Wernerian Natural History Society, which, under the auspices of the same professor, has long held a conspicuous place among the scientific associations of the country.