LYMPHATICS IN THE STOMACH OF THE EMBRYO PIG. 



the stomach. After Cunoo, 1902. 



1. The coronary or principal current. 



2. Right gastro-epiploic current. 



3. Splenic current. 



flow over the wall of the stomach and its appearance in regional lymphatic glands, he 

 has obtained a very good general idea of this question. As a result, he felt justified 

 in dividing the stomach into three main lymphatic zones (Poirier and Cuneo, 1902). 

 These arbitrary zones are shown in text-figure 1. The arrows show the direction 

 of the flow of lymph from the different parts. Zones 1 

 and 2 drain the glands of the lesser curvature, while the 

 flow from zone 3 goes to the hilum of the spleen and 

 then on to the pre-aortic glands. It is to be noted that 

 no drainage is indicated by way of the duodenum. 

 Cuneo states that most of the lymph flows directly 

 toward the lesser curvature and passes through glands 

 situated in this region, whose efferent ducts drain into 

 the pre-aortic lymph-nodes just anterior to the cy sterna 

 chyli. Zone 1 represents this area. In the area desig- 

 nated as zone 2 the flow of lymph is toward the pylorus, TEXT . FIQ . 1 ._ Lymphatic tcrritoricn , 

 as indicated, but passes posterior to it to the glands 

 of the lesser curvature. From zone 3 lymph passes 

 through vessels in related folds of peritoneum, to the 

 hilum of the spleen and from there to the pre-aortic lymph-nodes. 



As one looks at a cross-section of a stomach wall in which the lymphatics have 

 been injected, the extreme vascularity of the organ becomes immediately apparent. 

 The plexuses are so dense, permeate the entire organ so thoroughly, and are so rich in 

 their anastomoses that definite lymphatic zones and fixed points of drainage for the 

 different regions are anatomically difficult to establish. The more conservative 

 and apparently more accurate view is that the wall of the stomach contains four 

 complete lymphatic plexuses, in open communication with each other and through 

 which lymph may flow, peripherally, in any direction. It is quite difficult to con- 

 ceive of such dense, homogeneous plexuses being divided into any zone-like arrange- 

 ment. Certainly, the lymph will leave the stomach by way of the nearest and most 

 accessible avenue of exit, and injections made around the regions toward which 

 lymphatic flow occurs will apparently find zones in which most of the flow takes 

 place in a given direction; but in view of the complex nature of the vessels within 

 the wall of the stomach the accuracy of areas found in this manner becomes very 

 doubtful. Thus it is evident that our knowledge of the gastric lymphatics is not yet 

 complete. Such methods as those mentioned are sufficient only for the formation 

 of general ideas and beyond this point any statement is speculative. As yet, no 

 work has been done on the embryology of these vessels. To resolve such dense 

 lymphatic plexuses into their component parts by injection after they are fully 

 developed is obviously impractical. By a study of their origin and development it 

 was hoped that more accurate views might be adopted for the lymphatic drainage 

 of this organ, and it was with this idea that the present investigations in embryo 

 pigs were undertaken. 



By the method of injection, embryos can be studied in various stages before 

 the lymphatic development is complete. In this way the origin of the vessels, the 



