Disk-sphere Transformation in Mammalian Red Cells

THE purpose of this paper is to try to explain the phenomenon of the transformation of the mammalian erythrocytes from disks to spheres when a small drop of a saline suspension is placed between glass slide and cover-glass. Ponder (1934) several years ago reviewed the work which had been done in connexion with this phenomenon. As was pointed out by Ponder, who was the first to show clearly the necessity of having the glass surfaces in close proximity for the formation of perfect spheres (1928-9), the two explanations which have been put forth to explain the phenomenon are both inadequate. As will be seen later, that of Waller (1930) is somewhat closer to the true explanation than that of Brinkman & van Dam (1920). It will be shown that the phenomenon of sphering is a result of two changes which occur when the drop of suspension is placed between slide and cover-glass. One change is the increase in alkalinity of the suspension because of the alkaline nature of the glass surfaces. The other change is the adsorption on to the glass surfaces of a substance from the cell suspension. If this substance is present in the suspension, it will prevent the formation of spheres at the pM attained under the cover-glass, but if it is removed, as by adsorption, the cells will become spheres at that pH. Unless otherwise noted, all the cell suspensions used in the experiments about to be reported were suspensions of human erythrocytes in saline, made by adding 0-5 c.c. of whole blood, directly or within a few hours of drawing and oxalation, to 100 c.c. of 1 % NaCl. The observations on the cells of such a suspension were always made within 3 hr. of the formation of the suspension in order to avoid the changes in the red cells which occur on long standing. Also, unless otherwise stated, the slides and cover-glasses used in the experiments were of new glassware, wiped clean with a soft towel prior to being used. Several brands and grades of slides and cover-glasses were tested, but all responded the same as far as the sphering was concerned.