EQUILIBRATIONS IN PAETS OF ORGANISMS 



165 



tions. What would happen if put into solutions containing more 

 of the constituents of plasma or of interstitial fluid, is not known. 



Some fibroblasts are observed to engulf fluid from their sur- 

 roundings (Lewis, '31). This process of "pinocytosis" may be an 

 integral part of the exchanges concerned in turnover of water. 



d. Cells in fragmented tissues of mice were studied by Shear 

 ( '35) with respect to a particular kind of swelling by bulges. These 

 bulges occur commonly in either usual sodium chloride or Locke's 

 solutions. When later transferred to solutions containing gelatin 



0.05 



O05 QIC 0.15 

 Hours 



Fig. 100. Course of water load (% of Vo). A suspension of rabbit leucocytes in 

 equilibrium with Einger's solution is put at zero time into a similar solution but 0.4 as 

 concentrated. After 0.05 hour, salt is added to bring the solution back to 1.0 concen- 

 tration. Water load is estimated from the photoelectric potential created by a beam of 

 light passing through the suspension, after calibration. From Shapiro and Parpart 

 ('37). Redrawn by permission of the Journal Cell. Comp. Physiology. 



or other proteins the bulges diminish and disappear, at rates that, 

 unhappily, were not ascertained by micrometry. The vacuole-like 

 bulges might be counted as part of the cellular materials or not, as 

 one chooses. 



It is apparent that recoveries of water content may be studied 

 in single cells. Permeability itself is a regulated property; even 

 when fixed with respect to water, it allows the usual pattern of 

 equilibration by modifications of water exchange. Among cellu- 



