Inorganic Ions 



91 



ions cross body membranes, other things being equal, in a scries correspond- 

 ing to their mobiHties: K>Na>Ca>Mg; C1>S04. Specific differences in the 

 rate of penetration could, however, ^°- account for concentration differences 

 only if all the ions were lower in concentration inside than out. An ion could 

 not become more concentrated inside by fast diffusion alone. 



TABLE 13. COMPOSITION OF BODY FLUIDS BEFORE AND 

 AFTER DIALYSIS AGAINST SEA WATER'"- ^"^ 



a. Concentration in mg./g. HoO 



Animal 



Constituent 



Body Fluid 



Dialysed 

 Body Fluid 



Sea Water 



Echinus 

 esculentus 



Homarus 

 vulgaris 



Cancer 

 pagurus 



Protein 



Na 



K 



Ca 



Mg 



CI 



SO, 



H2O 



Protein 



Na 



K 



Ca 



Mg 



CI 



SO4 



Protein 



Na 



K 



Ca 



Mg 



CI 



SO4 



H2O 



0.3 



10.22 

 0.3746 

 0.3994 

 1.223 



18.59 

 2.601 

 985.4 



22.55 



11.71 

 0.5503 

 0.5874 

 0.1732 



18.26 

 0.7628 



34.94 



11.55 

 0.4684 

 0.5519 

 0.6583 



18.08 

 2.306 

 963 



10.19 

 0.3687 

 0.3950 

 1.220 



18.64 

 2.582 

 985.9 



22.605 



10.57 

 0.3773 

 0.4618 

 1.3085 



18.375 

 2.623 



34.88 



10.73 

 0.390 

 -0.463 

 1,301 



18.60 

 2.647 

 961 



10.3 



0.3744 

 0.3938 

 1.246 

 18.62 

 2.609 

 986.1 



10.45 

 0.3799 

 0.3995 

 1.264 



18.875 

 2.646 



10.47 

 0.380 

 0.4004 

 1.267 



18.93 

 2.652 

 986.1 



b. Composition of body fluid as per cent oF dialysis values 



Active Absorption. We are forced, therefore, to seek active forces in ionic 

 regulation; '-* some of these reside in the body membranes and some in 

 excretory organs. Krogh's studies of active absorption of ions have been men- 



