OEIGIN AND STEXICTUBE OF THE LYMPH 



175 



EiG-. 61 — Diagram of lymph relation. 



into the lymph spaces, and how does the lymph of these 

 spaces pass into the lymph tubes? The answer to this 

 question involves the whole mechanism by means of which 

 the tissue elements 

 receive their food 

 and get rid of their 

 wastes. In Figure 

 61 the relation of a 

 l3niiph tube, blood 

 tube, l3Tiiph space, 

 and tissue element 

 (cell) to one an- 

 other is indicated 

 in a diagrammatic 

 way. Let us ex- 

 amine this diagram for a moment, to see what explana- 

 tion it suggests for this problem. 



The first point to be noted is that between the Ijmaph 

 in the space and the plasma in the blood tube there is only 

 the thin membrane of the tube wall. Secondly, between 

 the lymph in the space and the liquid contents of the cell 

 is a second membrane, the cell wall. Finally, between the 

 lymph in the space and that in the Ijmiph tube is a third 

 membrane, the lymph tube wall. If we recall, what we 

 learned in regard to dialysis and osmosis (see p. 136) it 

 is evident that the above relation satisfies the conditions 

 necessary to those processes. By osmosis the dissolved 

 gases and some of the nutrients of the plasma together 

 with the water, pass through the walls of the blood vessel 

 into the lymph in the space, while in similar manner 

 the wastes in this fluid pass into both the blood vessel and 

 lymph tube. Furthermore, through the cell wall, the 



