The Origin and Development of the Lymphatic System

📙 This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 edition. Excerpt: ...sac, and along the ventral surface of the aorta, especially opposite the mesentery of the stomach and opposite the bifurcation of the trachea. I have studied them with care to see if they have any definite relation to the developing lymphatics and am sure that they have not. Sometimes they are near the lymphatics and sometimes not. Those in the thorax are not adjacent to the lymphatic plexus. They can be distinguished from the endothelial-lined lymphatics, but if one were convinced that lymphatics came from tissue spaces one might imagine transition pictures between the tissue spaces and the ducts. This is particularly true when the endothelium of a lymphatic vessel sags away from the surrounding tissue, a picture familiar to histologists in sections showing lymphatics in adult tissues. The further discussion of the thoracic duct is in part VIII. All of the primary lymphatic system is present in a human embryo measuring 30 mm. (Mall collection No. 86, fig. 13, Sabin 133, copied as fig. 493, Stricker 144). This stage represents the maximum size of the jugular sac. The dorsal arch is large and its line of separation from the jugular part is indicated by the perforation for the cervical nerves and blood vessels. The very small mesenteric sac and larger iliac sacs are distinct as well as the complete thoracic duct. 3. Primary Lymphatic System In Eabbit Embryos. In 1906 F. T. Lewis (76) published a valuable paper on the lymphatic system in rabbit embryos. Besides excellent reconstruction of the primary lymphatic system in rabbits, the cat and the pig, this paper has three important points: First, the discovery that the early lymphatics are filled with blood, which has proved to be of such value, now that its meaning is understood. Second, the...