102 George Heuer. 



which is taken from a pig of the same litter as Fig. 4, and is 

 drawn with the Wolffian body and kidney removed in order to show 

 the cistema chyli which lies dorsal to the aorta. In watching an 

 injection from the thoracic duct, the fluid usually runs down the 

 duct to a point just anterior to the suprarenal body, here the stream 

 divides and part runs into the anterior end of the mesenteric sac, 

 while the rest runs on into the cistema chyli. From here the central 

 part of the retroperitoneal sac fills up. As soon as this central 

 part is filled, the fluid runs from it into the anterior part of the 

 sac. An incomplete injection might lead one to think that the 



Fig. 5. — The cisterna chyli and posterior lymph sac from a pig 4.5 cm. long, 

 from the same litter as Fig. 4. The retroperitoneal sac has been almost 

 entirely removed to show the lymphatics dorsal to it. The three points of 

 anatomosis are marked in the drawing as 1, 2 and 3. The Wolffian body 

 and kidney have been removed from the left side, x 2.5. c. c, cisterna chyli ; 

 p. 1. s., posterior lymph sac ; t. d., thoracic duct. 



anterior end of the sac was a separate sac, while as a matter of fact 

 there is one continuous sac, corresponding with the position of the 

 entire group of preaortic nodes of the adult, a chain of nodes, which 

 extend from the level of the coeliac axis to the bifurcation of the aorta. 



It does not correspond in position with the so-called mesenteric 

 lymph nodes which are within the folds of the mesentery. Therefore 

 the sac is termed here the retroperitoneal lymph sac, rather than 

 retaining the name of mesenteric sac used by Dr. F. T. Lewis and ^Mr. 

 Bsetjer. 



The anatomosis of the posterior lymph sac with the retroperitoneal 

 sac is sho^vn in Fig. 5. This posterior sac receives three sets of 



