Symposium on the development and structure of the lymphatic system. I. The anatomy and development of the jugular lymph sacs in the domestic cat (Felis dornestica)

Prior to the meeting in 1907 the writers made an extensive study of the development of the veins of the cat in order to explain from an embryological standpoint the large series of venous abnormalities which had been collected by them in the preceding years.In the course of this investigation they were impressed by the circumstance that the main lymphatic channels not only developed in close relation to the veins, but also observed, as did Lewis in the rabbit, that many of the embryonic veins appeared to be actually replaced by lymphatics in the later stages of development.A marked reciprocal relationship also appeared to exist between certain embryonic venous channels undergoing atrophy and the developing lymphatics, in the sense that as these venous channels gradually atrophied spaces were formed outside their intima which, subsequently, through fusion and growth, invaded the territory, wholly or in part, formerly occupied by the veins.On account of this reciprocal relationship between veins and lymphatics the writers' advanced the view, at the meeting in 1907, that the main lymphatic channels of the cat begin as extra-intimal spaces along the course of * The following nine papers were read at the twenty-third session of the Associa-'American Journal of Anatomy, Vol.VI, 1907.tion of American Anatomists, Chicrtgo, January 1 , 2 and 3, 1908.'The reconstruction from which Fig. 12 was drawn was made of an embryo belonging to the Harvard Embryological Collection (Series 474, 10.7 mm.embryo), and we take this opportunity of thanking Professor Minot for his courtesy In placing this as well as several other series of embryos at our disposal.