48 Florence B. Sab in. 



the primary lymphatic system in rabbits, the cat and the pig, this paper 

 has three important points: First, the discovery that the early lym- 

 phatics are filled with blood, which has proved to be of such value, 

 now that its meaning is understood. Second, the discovery of the 

 retroperitoneal sac which he described as lying adjacent to the mesen- 

 teric veins. He also showed the iliac sacs and cisterna chyli; all of 

 which we now know come from the renal veins (Sabin 136). Third, 

 he noted that lymphatic ducts when they are reconstructed from sec- 

 tions appear as a row of beads. Since these rows of beads occurred 

 along the veins in his reconstructions and since he could not find the 

 connections of the early sacs with the veins he was led to suggest that 

 lymphatics might arise from multiple anlagen split off from the veins 

 along their course. The apparently isolated endothelial-lined vessels 

 found in serial sections we call Meyer-Lewis anlagen. They are dis- 

 cussed in section VIII. 



The jugular sac in rabbits has an early extension along the primitive 

 ulnar vein like that of the human embryo. The dorsal portion of the 

 sac, for the posterior triangle of the neck, arises from a large stalk 

 from the primary jugular portion between the level of the 4th and 5th 

 cervical nerves. 



4. Primary Lymphatic System in the Cat. 



The primary lymphatic system in the cat will be described from the 

 extensive work of Huntington and MeClure (51-58 and 91-94), one 

 reconstruction of Lewis (76) and a few injections of my own. The 

 work of Huntington and MeClure has been mainly on the development 

 of the jugular lymph sacs and the thoracic duct in the cat and their 

 observations are for the most part brought together in two extensive 

 papers (54 and 58). Their work is difficult to analyze and cannot 

 be done entirely accurately without seeing their sections. They have 

 relied on the appearances of sections and the appearances of wax models 

 from them to differentiate lymphatics, and since these are not ade- 

 quate criteria it is impossible to be sure that all the structures shown 

 as lymphatics are lymphatics ; in fact, one can be certain that some of 

 them are not. Their theories in regard to the origin and development 

 of the lymphatic system are discussed in sec. VIII. In the article 

 (54) on the jugular lymph sac of the cat figs. 8 to 21 may be disre- 

 garded as evidence, since they are diagrams. Figure 22, which they 



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