3 PHYSICAL CHEMISTRY IN MEDICINE. 



into the equilibrium between substances that dissolve 

 and those that inhibit the solution of red blood-corpuscles, 

 and the reversibility of the migration of color, can we 

 know in how far haemolysis through crystalloids represents 

 a single process. The idea that the exit of haemoglobin 

 from the red blood-corpuscles does not represent a single 

 change, as rendered apparent through the action of such 

 various agents as electricity, cold, various poisons, etc., 

 has found valuable support in the investigations of 

 STEWART on the permeability of red blood -corpuscles 

 to various salts (determination of electrical conductivity 

 of plasma). Only the failure to recognize this fact is 

 responsible for the extensive use that has been made of 

 the determination of the osmotic resistance of the eryth- 

 rocytes in the solution of questions in the physiology 

 and pathology of the blood, for which this method was 

 never adapted. We do riot understand the conditions 

 under which the physiological destruction of the red blood- 

 corpuscles, with a splitting off of their coloring- matter, 

 occurs, and neither the discovery of normal nor of patho- 

 logical values for their osmotic resistance yields any data 

 from which conclusions regarding their behavior under 

 experimental (for example, removal of the spleen) or 

 pathological conditions (icterus, haemoglobinuria, etc.) 

 may be drawn. In fact, the beautiful investigations of 

 BORDET, EHRLICH, LANDSTEINER, etc., on the production 

 of haemolytic substances in the animal body point to a 

 new field of work entirely outside of the teachings of 

 osmotic pressure. 



There is no objection to saying that several solutions 

 which have the same osmotic pressure are isotonic, that 

 is, isosmotic with each other; but to speak of the isoto- 



