RELATION OF LYMPHATIC TO BLOOD-VASCULAR SYSTEM 11 



II. The lymphatic vessels are directly derived from the 

 venous system, certain embryonic venous channels being trans- 

 ferred in toto to the lymphatic system. 10 ' 11 ' 12 - 13 



III. All systemic lymphatics are formed by union of multiple 

 direct derivatives from the embryonic veins, 14 or only the thoracic 

 ducts are so developed, while the other systemic lymphatic ves- 

 sels arise independently. 15 



IV. The mammalian lymphatic system as a whole is developed 

 by blind ducts which "bud off" from the embryonic veins of the 

 cervical, and later from those of the inguinal region, widen out 

 to form sacs, from which lymphatics grow to the skin and "cover 

 its surface, while at the same time a growth of ducts occurs along 

 the dorsal line following the aorta to make a thoracic duct from 

 which lymphatics grow to the various organs." The theory under- 

 lying this conception of lymphatic development assumes the 

 primary formation of a number of sacs, derived from the veins, 

 and lined by embryonic venous endothelium, from which, as the 



111 C. Langer: "Ueber das Lymphgefasssystems des Frosches." Sitzb. d. Akad. 

 </. Wissensch, Bd. Iviii., I. Abth., 1868. 



11 L. Ranvier: Comptes Rendues, 1895, 1896. "Morphologic et developpement 

 des vaissaux lymphatiques chez les mammiferes." Archives d' Anatomic Micro- 

 scopique, Tome I, 1897. 



12 Giuseppe Favaro, "Richerche intorno alia morfologia ed allo sviiuppo dei 

 vasi, seni e cuori caudali nei Ciclostomi e nei Pesci," Atti del Reali Institute Veneto 

 di Scienze, Letters et Arti., anno accad. 1905-1906, Tomo Ixv, Parte seconda. 

 Appendice alia Dispensa X. "Note fisiologiche intorno al cuore caudale dei 

 Murenoidi (Tipo Anguilla vulgaris, Turt.)," Archiv. di Fisiologia, vol. ii, Fasc. 

 v, Luglio, 1905. "II cuori ed i seni caudali dei Teleostei," Anat..Anz., xxvii. Band, 

 no. 14 und 15, 1905. 



13 W. F. Allen, "The Distribution of the Lymphatics in the Head and in the 

 Dorsal, Pectoral and Ventral Fins of Scorpaenichthys mamoratus," Proc. Wash- 

 ington Acad. of Sciences, vol. viii, pp. 41-90, May 18 1906. "The Distribution of 

 the Subcutaneus Vessels in the Head region of the Ganoids, Polyodon and Lepi- 

 dosteus," ibid., vol. ix, pp. 79-158. July 1907. "The blood-vascular system of 

 the Loricati, the mail-checked fishes," ibid., vol. vii, 1905. 



"Distribution of the subcutaneous vessels in the tail region of Lepisos- 

 teus," Am. Jour. Anat. vol. viii, 1908. 



14 F. T. Lewis: "The Development of the Lymphatic System in Rabbits." 

 Am. Journ. of Anat., vol. v, 1905, pp. 95-111. 



15 C. F. W. McClure: "The Development of the Thoracic and Right Lymphatic 

 Ducts in the Domestic Cat." Anat. Anz., xxxii. Band, No. 21 and 22, 1908, p. 

 534. 



