ABSTRACT
This paper is concerned with certain properties of the mammalian red cell ghost. The principal conclusions are:
When red cells are haemolysed by water they increase in volume, changing their shape and becoming spheres. If the degree of hypotonicity is sufficient they haemolyse in the spherical form, but quickly resume the form of disks, even in hypotonic solutions. If the haemolytic systems are rendered isotonic by the addition of salts, the cells shrink temporarily, but finally assume their original volume and shape. It seems that when there are no osmotic forces acting on it, the watery ghosts tend to take up the volume and shape from the red cell from which it was derived.
When a red cell haemolyses in a hypotonic medium and becomes a ghost, a considerable amount of haemoglobin is retained, perhaps by adsorption. It is doubtful whether this adsorption could be on a purely surface structure ; to account for the results we might have to postulate an internal structure in addition.
After haemolysis by water, red Cells will not form spheres between slide and coverslip, nor by the addition of lecithin. If the watery ghosts are made by precipitation with CO2, no sphering can be observed between slide.and slip, with lecithin, with saponin, or with rose bengal. In the case of the watery ghost, the “form component” seems to be preserved, for the ghosts are biconcave disks; the surface, however, must have been altered, for disk-sphere transformations no longer take place.
Using conductivity methods, Fricke & Curtis (1934) came to the conclusion that when red cells are haemolysed with from 3 to 19 parts of water the volume of the ghosts is from 1·45 to 1·65 times that of the original cell, with an average value of 154. In making the computations they assumed that the ghosts are spheres instead of disks. Using the proper form factor, 1/X = 0·8 instead of 0·5 reduces their average value to 1·34. This is certainly greater than the figure lit (or ti I %), which I have obtained and think of as being the same as unity, but Fricke’s methods of computation are indirect. At al) events, considering that Fricke and Curtis’s tonicity must have been in the neighbourhood of 0·25, their results are not essentially opposed to mine.
If we regard the haemoglobin molecule as an oblate spheroid or as a cylinder, which are more likely shapes than that of a sphere (cf. Neurath, 1939), the results are not so good. Assuming a spheroid with major axis 158 A and with minor axis 31-6 A, the projected area of each molecule might be as much as 3900 A, and so the number of layers at the surface might be, not 4, but about 14.
The method for preparing entirely haemoglobin-free ghosts will be described by A. J. Parpart, who has kindly communicated it to me and to R. F. Furchgott.
Measurements of the concentrations with the colorimeter are much more satisfactory than determinations of the extinction coefficients with an instrument such as the Stufenphotometer. This is partly due to the difficulty in working visually at 4300 A.
