110 The Development of the Lymphatic System in Rabbits 
SUMMARY. 
The lymphatic system of rabbits begins along the internal jugular vein 
as a detached sac formed by the coalescence of several venous outgrowths. 
Similar though smaller sacs arise from the subcardinal and mesenteric 
veins at a slightly later date. 
Subsequently lymphatic vessels develop along the courses of the azygos 
and cutaneous veins, apparently from independent venous outgrowths. 
All of these vessels unite with one another to form a continuous system, 
which acquires new and permanent openings into the veins near the 
subclavian termination. 
The first lymph nodes observed are two pairs, one beside the sub- 
scapular vessels, and the other beside the ilio-lumbar vessels. 
In order to facilitate comparison with Prof. Sabin’s work, the following 
conclusions may be added: 
The lymphatic system does not arise from the venous system by four 
outgrowths, but by several. It is not always in communication with the 
veins. The outlets of the thoracic and right lymphatic ducts are not per- 
sistent primary openings. An identification of mammalian lymph hearts, 
comparable with those of the amphibia, should not be made, on the evi- 
dence now available. Judged by their relation to the early lymph nodes, 
the jugular sac is not comparable with the lymphatics along the ilio- 
lumbar vein. However, the study of rabbit embryos confirms the chief 
conclusion established by Prof. Sabin, that the lymphatic system is a 
derivative of the venous system. 
LITERATURE CITED. 
GAGE, Simon H., o2.—A Reference Handbook of the Medical Sciences. Edited 
by Albert H. Buck. 2d ed., Vol. 5, pp. 624-659, New York. 
Gaupp, ERNST, 99.—Anatomie des Frosches. 2d ed., Part 2, Braunschweig. 
HOCHSTETTER, FERDINAND, 93.—Beitrage zur Entwicklungsgeschichte des 
Venensystems der Amnioten, III. Morph. Jahrb., Vol. 20, pp. 543-648. 
KRAUSE, W., 68.—-Die Anatomie des Kaninchens. Leipzig. 
LANGER, C., 68.—Ueber das Lymphgefasssystems des Frosches, III. Sitz.-Ber. 
d. Akad. d. Wiss., Wien, Vol. 58, pp. 198-210. 
Lewis, FREDERIC T., 02.—The development of the vena cava inferior. Amer. 
Journ. of Anat. Vol, 1, pp. 229-244. 
MacCatitum, W. G., o2.—Die Beziehung der Lymphgefiasse zum Bindegewebe. 
Arch. f. Anat. u. Phys., Anat. Abth., pp. 273-291. 
Ranvier, L., 97—Morphologie et développement des vaisseaux lymphatiques 
chez les mammiféres. Arch. d’Anat. mic., Vol. I, pp. 69-81. 
SABIN, FLORENCE R., 02.—On the origin of the lymphatic system -from the 
veins and the development of the lymph hearts and thoracic duct in 
the pig. Amer. Journ. of Anat., Vol. 1, pp. 367-389. 
