The effect of washing on the resistance of erythrocytes to hypotonic hemolysis.

Brinkman and van Dam 1 claim to have shown that the resistance of rabbit erythrocytes to hypotonic hemolysis is increased by washing them in a physiologically balanced solution, while Snapper 2 publishes data tending to show that washing in 0.9 percent NaCl decreases their resistance. This difference is not necessarily a general one due to the chemical composition of the solutions, as appears from the following experiments:

Blood was taken aseptically by heart puncture from a dog and from four guinea pigs whose blood was pooled. The blood was defibrinated by shaking with fragmented glass. 1.5 cc. of each kind of cell was suspended in 15 cc. of Ringer-Locke's solution lacking phosphate and bicarbonate, and a like amount in 15 cc. of 0.9 percent NaCl. After about ten minutes these, together with samples of undiluted defibrinated blood, were centrifuged, and the supernatant liquid drawn off so as to leave the total volume 15 to 20 percent in excess of that of the cell sediment, which was then stirred up in this volume.

Portions of 0.05 cc. of each of the six lots were added to 2.5 cc. of each of several appropriate dilutions of 0.9 percent NaCl, centrifuged, the supernatant liquid decanted, and the sediment of cells hemolysed in 2.5 cc. of distilled water. The color of both the decantate and the hemolysed sediment was then measured by comparison with a Madsen scale and the amount of hemolysis in percent calculated from these data. The method of calculation and the necessary corrections have been described. 3