326 Distribution of Ibdme -In. Thyroid Gland. II 



cells as they lie suspended in Ringer's solution during the sepa- 

 ration of the colloid material. If it is assumed that such an 

 outward diffusion takes place, it seems reasonable to expect that 

 the iodine compound should diffuse back into the cells if we should 

 increase the concentration of that iodine compound in the Ringer's 

 solution in which the cells are suspended. Several experiments 

 like those given in Table I were undertaken to determine whether 

 or not the iodine content of the cells could thus be increased. 



TABLE I. 



Effect of Floating Cells on Pure Ringer's Solution and on Ringer's Solution 

 on Which Cells of an Iodine-Rich Gland Had Been Floated. 



It may be seen from the data given in Table I that no increase 

 in the iodine content of cells could be brought about by increas- 

 ing the concentration of the characteristic iodine compound in 

 the Ringer's solution. 



Again the iodine concentration of the cell mass does not seem 

 to be in the least altered whether or not the freshly centrifugalizecl 

 cell mass is washed several times with iodine-free Ringer's solution. 



Moreover, in the attempt to find a suspending medium more 

 nearly related physicochemically with thyroid cells than is Rin- 

 ger's solution, I have used fresh dog serum and have not found 

 the iodine content of the cells measurably different from that of 

 control cells suspended in Ringer's solution. 



