Abstract
There have been several reports on the action of tannic acid upon red blood cells (1, 2). The present paper is concerned with observations indicating that tannic acid acts upon mammalian red blood cells, rendering them resistant to streptolysin-S, an oxygens'able hemolysin of Streptococcus pyogenes (3, 4), in such a manner that the lost susceptibility of the tanned cells can be readily restored by treating them with certain proteins.
