Alterations in the diameter of erythrocytes during hæmolysis

There has been some doubt as to the manner in which certain substances produce hæmolysis, especially saponin, bile salts, and those hæmolysins which are the result of immunity experiments. The doubt has even been extended to the mode of action of hypotonic saline, the hæmolytic action of which is generally put down to the osmotic changes which it produces. Bechhold (1), however, considers that surface tension phenomena have much to do with this hæmolysis. As regards saponin, some observers consider that it destroys the cell wall (Arrhenius (2)), whereas others consider that it produces hæmolysis by lowering of surface tension; others, again, deny that there is any relation between surface tension and hæmolytic activity in the case of the saponins (Woodward and Alsberg (3)). The same doubt prevails regarding bile salts, it being considered by many that they dissolve the lipoid envelope, and by others that surface tension plays an important part. As regards hæmolysis by hæmolytic amboceptors, it is suggested by some that the action is due to a sudden change in the permeability of the envelope (Clowes (4)), and by others that the lipoids are attacked (Jobling and Bull (5)); or, again, that “osmotic pressure is altered” by the action of the hæmolysin (McDonagh (6)). Assuming what is generally admitted, that the red cell consists of an envelope containing a fluid or semi-fluid substance, some information may be gained by studying the changes of form which such a body would undergo under the various conditions of osmotic pressure, surface tension stress, or chemical action, and comparing with these the changes in form which may be observed in the red cell under the action of hæmolytic substances.