The subject of animal parasites upon and in the human body, while certainly not one of the most attractive on a superficial view, has yet been found to yield scientific material of the highest interest, and has required great energy and care to produce satisfactory results. Among British workers in this field none is more widely known than Dr. THOMAS SPENCER COBBOLD, F.R.S. Dr. Cobbold is the third son of the late Rev. Richard Cobbold, rector of Wortham, Suffolk, the author of the striking “History of Margaret Catchpole,” and his grandmother, Mrs. Cobbold, was a zealous geological collector in the early days of geology, having a fossil species of mollusc (_Nucula Cobboldiæ_) named in her honour. The subject of this notice was born at Ipswich in 1828, and educated for some years by the Rev. H. Burrows, at Yarmouth, and afterwards at the Charterhouse. Young Cobbold entered upon the study of medicine at the Norfolk and Norwich Hospital in 1844, as pupil of Mr. Crosse, F.R.S. Later he proceeded to Edinburgh, and became class-assistant to Professor Hughes Bennett, and prosector to Professor Goodsir, then at the height of his career. Such men, and especially Goodsir, exercised a great awakening influence on young Cobbold, and deepened his strong tendencies towards anatomical research. In 1851 Dr. Cobbold graduated on the same day as Dr. Burdon-Sanderson, now Waynflete Professor of Physiology at Oxford, and the late Dr. Charles Murchison, all three being gold-medallists. After studying for some time in Paris, Dr. Cobbold on his return to Edinburgh was appointed curator of the Anatomical Museum, and became active in dissecting specimens of animals received at the museum. Among others his memoir on the giraffe and other ruminants formed the basis of his article Ruminantia, contributed to Todd and Bowman’s Cyclopædia of Anatomy and Physiology. When the lamented Edward Forbes was elected to the chair of Natural History, Dr. Cobbold’s attention was powerfully attached to geology, and for some years he made excursions with his class, and collected large numbers of fossils. More distant excursions to Arran, the Yorkshire and Devonshire coasts, the Isle of Wight, &c., supplied Dr. Cobbold with specimens of great service in illustrating the Swiney Lectures, which he afterwards delivered for five years with marked success at the British Museum and at the Royal School of Mines (1868-72). So popular did these lectures become that towards the close of the last course many of the visitors could not find seats.