CRYSTALLOID IN LIVING CELLS 327 



up and giving out water and substances in solution, furnish a 

 clear demonstration that neither osmosis nor any other physical 

 hypothesis which leaves out the peculiar and varying chemical 

 constitution of bioplasm can yield an explanation of absorption, 

 secretion, or excretion. 



The whole of the experiments lend support to the view that 

 the living cell exists in a periodically or phasically varying osmotic 

 equilibrium with its surroundings, and not in a state of osmotic 

 equality with them. The cell by its union with crystalloids pre- 

 serves a distinct osmotic condition within its bounds different 

 from that in the surrounding fluid media from which its nutrient 

 materials are taken up. This is particularly well seen when the 

 medium without is subject to considerable and accidental varia- 

 tions. Even in those cases where the outer medium is practically 

 constant, as in the extreme case, for example, of blood-corpuscle 

 and plasma, although there appears to be an existence of osmotic 

 equality within the cell and without, yet this is due to the peculiar 

 conditions having induced a close coincidence of the two sets of 

 osmotic phenomena, and the existence of an equilibrium and not 

 an equality may be easily shown by suitably varying the condi- 

 tions. So that even in these extreme cases what we have to do 

 with is not really equality of osmotic pressures, but an equilibrium 

 which happens to simulate equality from the presence of reducing 

 conditions; the equality disappears as soon as these reducing con- 

 ditions are disturbed. 



When the corpuscles of whipped blood are separated as com- 

 pletely as possible from the serum by means of the centrifuge, 

 and the depressions of freezing-point of the corpuscles and of the 

 serum separately determined, it is found that the freezing-point 

 of the serum lies on the average at 0-02 to 0-03 C. lower than that 

 of the corpuscles. This difference, small as it is, is constant in its 

 occurrence, and corresponds to a difference in osmotic pressure 

 of approximately 200 to 300 rnrns. of mercury. If the corpuscles 

 after separation from the serum are thoroughly shaken up with 

 saline solutions weaker and stronger than the serum, or as they 

 are termed, hypo- and hyper-tonic solutions, it is always found, on 

 again separating corpuscles and saline by means of the centrifuge, 

 that the depression of the freezing-point of the saline is greater 

 than that of the corpuscles, no matter whether the saline employed 

 was nypotonic or hypertonic. The differences become in these 



