36 FATE OF PRIMARY LYMPH-SACS IN ABDOMINAL REGION OF PIG, ETC. 



their origin from the iliac sacs, and a fairly large node anterior to the vessels suggests 

 its origin from the retroperitoneal sac. The separation of the juxta-aortic glands 

 by the vena cava, into a prevenous and a retrovenous group which were formed 

 from lymph-sacs ventral and dorso-lateral to the aorta, is shown in the right side 

 in figure 5, where the double drainage from the kidney to these two sets of glands 

 at the hilum is indicated. 



In young embryos, vessels from the region of the inferior mesenteric artery pass 

 to the colon, and in later stages glands are seen about the inferior mesenteric artery, 

 evidently draining the descending colon. 



The drainage from the ovaries and testes is by vessels that accompany the 

 correspondingly named arteries, first through one or two secondary nodes, then to 

 the lumbar region, where these lymphatic trunks turn medially and run toward 

 their terminal glands, which are situated ventral or ventro-lateral to the aorta and 

 vena cava, extending from the bifurcation of the aorta to about the level of the 

 posterior pole of the kidneys; that is, to pre-aortic, prevenous, and juxta-aortic 

 glands in the lumbar region. To these same glands drains part of the lymph from 

 the body of the uterus and Fallopian tubes in the female and from the epididymis 

 in the male. These glands have been formed from the root of the genital branch 

 as it comes off from the posterior end of the retroperitoneal sac (fig. 1, V. 1. gon.). 

 When the horns of the uterus are injected, the flow is both toward the cervix and 

 peripherally toward the tubes. The medial portion of the horn and part of the 

 cervix drain to a very large gland at the bifurcation of the external and internal 

 iliac arteries. Thus the lymph from the sexual glands has only one channel of flow, 

 i. e., to the glands that were formed from the posterior portion of the ventral or 

 retroperitoneal sac. The lymph from the excretory canals of the sex-glands, on 

 the other hand, has a double course of flow; that from the structures originating 

 proximal to the sex-glands goes to the glands formed from the ventral sac, while 

 the portions of the excretory canals distal to the sex-glands drain to glands arising 

 from the primary lymphatics dorso-lateral to the aorta. 



Injections of the bladder showed lymphatics draining to the external iliac 

 glands. Drainage from certain regions of the bladder passed through intermediate 

 lateral vesicle glands peripheral to the iliac nodes. Occasionally a vessel could be 

 injected to the glands at the bifurcation of the aorta. 



The lymphatics from the posterior trunk of the iliac sac become transformed 

 into a chain of lymph-glands which are disposed fairly regularly about the blood- 

 vessels (fig. 5, Lymgl. il. com.). In general, they are similar to those described by 

 Poirier and Cuneo (1904), except that there is a characteristic ilio-inguinal node in 

 the pig which is not seen in man. 



The inguinal glands drain the superficial lymphatics over the lower abdomen, 

 external genitalia, ventral side of the tail, the leg, and the medial side of the thigh. 

 The efferents of the inguinal glands are distal external iliac nodes. 



An ilio-inguinal node (fig. 5, Lymgl. ilio-ing.), characteristic of the pig, lies in 

 the course of the ilio-lumbar artery near the crest of the ilium. It drains the super- 

 ficial lymphatics of the posterior body-wall, down over the hip and the root of the 

 tail (Sabin, 1904). 



