In a verbal notice of researches into the nature of the thyroid, thymus, and suprarenal bodies, Mr Goodsir stated that these three anomalous organs, situated respectively in the neck, chest, and abdomen, are in the embryo connected together in the form of two continuous masses, one on each side of the spine, from the base of the cranium to the origin of the omphalo-mesenteric arteries. The first or abdominal portion of each of these masses, grouped around the origins of the omphalo-mesenteric arteries, become the supra-renal capsules. The middle or thoracic portions, situated in the lateral parts of the thorax, where the lungs, at this period in the middle line, are afterwards to be, pass forwards to give place to the latter, and unite across the front of the pericardium, and become the thymus gland.