180 INJURY, RECOVERY, AND DEATH 



viscosity) while in CaCl 2 we should expect to find 

 increased resistance (due to increased viscosity) followed 

 by a fall of resistance (due to coagulation or other struc- 

 tural change in the protoplasm). 



It soon became apparent that there were several 

 serious objections to this conception. The most impor- 

 tant of these may be briefly stated as follows : 50 



1. If to a solution of NaCl we add CaCl 2 until the 

 increase of viscosity produced by one salt is just balanced 

 by the decrease produced by the other, the resistance 

 should remain stationary. This is not the case: there 

 is always a fall, or a rise followed by a fall, of resistance. 



2. If more CaCl 2 be added there should be a rise of 

 resistance : this should after a while become stationary, 

 provided there is not enough CaCl 2 to produce the coagu- 

 lation or other structural change which decreases 

 the resistance. This does not occur: the tissue never 

 maintains its increased resistance, but shows a fall of 

 resistance which begins soon after the maximum 

 is reached. 



3. If still more CaCl 2 be added, so as to produce the 

 coagulation or other structural change which decreases 

 resistance, we should expect to find in all cases the same 

 viscosity (and consequently the same maximum of resist- 

 ance) just before the fall begins. Still further increase 

 of CaCl 2 would only hasten this process without changing 

 the maximum. This does not correspond with the facts. 

 The maximum steadily rises as the proportion of CaCL 

 increases, so that the greatest maximum is found in 

 pure CaCL. 



4. If the fall of resistance in CaCl 2 is due to coagula- 

 tion, or to some other structural change, it might be 

 expected to be irreversible almost from the start; but this 



CO 



Cf. Osterhout (1916, B) . 



