LYMPH FLOW 



177 



composition. The fact that the lymph tubes are continu- 

 ally draining off the liquid they receive, and that the 

 plasma is being constantly renewed, together with the vary- 

 ing activity of the cell, makes the composition of the three 

 liquids subject to constant change. It is this change that 

 gives a definite direction to the flow. While it is true that 

 some substances pass from the lymph tubes into the space, 

 and from the space into the blood tube, the prevailing 

 direction of flow is from blood tube to space to lymph tube, 

 and in this way most of the cell wastes are carried into the 

 lymph tubes. What then becomes of these v/astes which 

 enter the lymph tubes? 



The lymphatics. — The Ijrniph tubes just referred to are 

 only the ultimate tiny endings of a branch- 

 ing network of tubes called the lymphatics. 

 From all parts of the body these tiny tubes 

 (lymph capillaries) are collected together, and 

 finally empty their contents into two large 

 tnmks on each side of the body. These 

 trunks are of different size, the one on the 

 left side with its branches being much the 

 larger. It is this left branch that includes 

 the system of branches called the lacteals 

 (seep. 135). Both the right and left branches 

 open finally into two veins on the right and left 

 sides of the neck. In short, then, the waste 

 laden lymph is finally drained from all parts of 

 the body and poured into the blood again at 

 such points that the wastes must pass through 

 the lungs before entering the general circula- 

 tion and are finally eliminated by the kidneys. 



Lymph flow. — Unlike the blood system, there is no 



Fig. 63 — Lymph 

 tubes, showing 

 valves, d. 



EDDY. PHYS. — 12 



