14 



LYMPHATICS IN THE STOMACH OF THE EMBRYO PIG. 



CONCLUSIONS. 



1. From a study of development of the lymphatics in the stomach of the embryo 

 pig, it is found that they invade that organ at two principal points, viz., the lesser 

 curvature, by way of the gastro-hepatic ligament, and the greater curvature, via 

 the ligaments of the spleen. 



2. Arising in common with the gastric lymphatics is a large trunk which passes 

 to the duodenum, then up along the duodenum to the pylorus, anastomosing 

 freely with the lymphatics on the posterior surface of the stomach. 



3. Part of the lymphatics invading the stomach at the lesser curvature, early 

 in their growth, form a dense periesophageal plexus of vessels in the subserosa. 



4. From this periesophageal ring, as well as from the other vessels reaching the 

 stomach at both lesser and greater curvatures, branches are given off at right 

 angles on both the anterior and posterior walls of the stomach. These vessels 

 finally meet and encircle the stomach in a segmental manner similar to that' de- 

 scribed by Heuer for the intestine. There are a number of connections between 

 these segmental subserous trunks, forming them into a subserous plexus. 



5. During the development of this plexus numerous branches from its trunks 

 pierce the layers of the stomach and form other gastric plexuses. All of these are 

 homogeneous layers of lymphatic vessels. 



6. The richness of the gastric plexuses and their numerous anastomoses preclude 

 the theory of any sharply defined areas whose drainage would take place in constant 

 given directions. 



7. There are four general pathways by which lymphatic drainage may take 

 place: (a) the lesser curvature, (b) the greater curvature, (c) the duodenum, and 

 (d) the esophagus. 



I wish to thank Professor F. R. Sabin and Dr. R. S. Cunningham for the valua- 

 able assistance they have given me in this work, and to express my appreciation to 

 Mr. J. F. Didusch for the illustrations. 



REFERENCES. 



BAETJER, W. A., 1908. The origin of the mesenteric sac and 

 thoracic duct in the embryo pig. Amer. Jour. Anat., 

 vol. 8. 



CASH, J. R., 1917. On the development of the lymphatics in 

 the heart of the embryo pig. Anat. Rec., vol. 13. 



, 1919. On the development of the lymphatics of the 



btomach of the embryo pig. Anat. Rec., vol. 16, p. 145. 



CUNEO, B., 1902. Systemelymphatique,(PoirierandCuneo). 

 Traite d'anatomie humaine, Poirier and Charpy. 



CUNNINGHAM, R. S., 1916. On the development of the 

 lymphatics of the lungs in the embryo pig. Contri- 

 butions to Embryology, vol. 4, Carnegie Inst. 

 Wash. Pub. No. 224. 



GRAY, H. Anatomy. Lewis ed. 



HEUER, G., 1909. The development of the lymphatics in 



the small intestine of the pig. Amer. Jour. Anat., 



vol. 9. 

 JAMIESON, J. R., and J. F. DOBSON, 1907. The lymphatic 



system of the cjecum and appendix. Lancet. 

 KEIBEI, & MALL, 1912. Human Embryology. 

 MALL, F. P., 1896. The vessels and walls of the dog's 



btomach. Johns Hopkins Hosp. Reports, vol. 1. 

 SABIN, F. R., 1913. The origin and development of the 



lymphatic system. Johns Hopkins Hosp. Reports. 



vol. 17. 



