620 LYMPHATIC SYSTEM. 



colourless, coagulable, imbibed fluids are moved forwards 

 to the blood by the vis absorbendi, the pressure and move- 

 ments of all surrounding parts, and by the direction of the 

 valves now crowded in their interior. The valves, as in por^ 

 tions of the venous system, are sometimes deficient in their 

 interior, as in the lungs, the liver, and the uterus, and not- 

 withstanding their distinct fibrous coat, considered by Meckel 

 and others to be muscular, and the obvious rithmic pulsa- 

 tions of their muscular sacs in many of the lower vertebrata, 

 no pulsatory movements or spontaneous contractions have 

 yet been discovered in any portion of the lymphatic system 

 of man or mammalia. 



The general distribution or the typical form of this vast sys- 

 tem in the mammiferous animals, is seen in that of the human 

 body where, as usual, they have been detected and most in- 

 vestigated, after their discovery in inferior tribes. Collecting 

 the lymph from the superficial parts of the feet, these vessels 

 form an outer cutaneous group, ascending behind the exter- 

 nal ankle and the back part of the leg to the small popliteal 

 glands, and an inner cutaneous group, ascending along the in- 

 ner side of the knee and forepart of the thigh, to the superfi- 

 cial inguinal glands. From the deeper parts of the feet the 

 lymphatics collect around the arterial trunks, as the cutaneous 

 do with the great veins, and ascending with the peroneal, the 

 anterior and the posterior tibial arteries, they traverse the 

 popliteal glands, and continue their course with the femoral 

 artery to the smaller and deeper seated glands around that 

 vessel in the inguinal region. Throughout their whole course 

 these lymphatic trunks are reinforced by numerous branches 

 from all the surrounding parts, and numerous lymphatics 

 from the exterior of the pelvis, the abdomen, and the ge- 

 nital organs, likewise meet to traverse the inguinal glands. 

 The efferent lymphatics from both sets of inguinal glands 

 enter the pelvis, through the crural arch, with the great 

 blood-vessels, and proceed along the external iliac artery to 

 the large and numerous lumbar glands, and all the arte- 

 rial trunks issuing from the pelvis are accompanied by nu- 

 merous lymphatics from the neighbouring parts, proceeding 

 inwards to the same destination, and thence to the thora- 

 cic duct. 



The absorbents from the urinary bladder, the prostate, the 



