264 FINE-STRUCTURE OF PROTOPLASM II 



dismiss this network as mere artefact. To their way of thinking, the 

 erythrocyte consists merely of a balloon-like membrane, a view which 

 has some backing through the absence of any microscopic structure 

 in the Hving cell interior as seen in the ultra microscope or illuminated 

 by ultraviolet rays. This view is also shared by most of the research 

 workers who have studied haemolysis. For, if the erythrocytes are 

 damaged mechanically, either by heat or freezing, or by immersion in 

 sufficiently hypotonic or hypertonic solutions, the contents of the cell 

 extravasate with the red blood pigment and a colourless sheath re- 

 mains, which is called ghost, or the stroma. 



These facts notwithstanding, the contents of the erythrocytes are 

 not to be considered as a sol-like liquid of no organized intrinsic 

 structure, an error committed by the older investigators and, more 

 recently, by Gough (1924'). The relative viscosity of the cell contents 

 is 30 (see Table XXII, p. 169) and Ponder (1934) states that the interior 

 of the cell shows respiration like other cells. Although the erythrocyte 

 membrane has been proved to contain all the chemically identifiable 

 substances of the blood corpuscles with the exception of the blood 

 pigment and the salt content, the assumption clearly must be that the 

 contents of the cell, far from being an unorganized liquid, is a partially 

 gelated cytoplasm, the organization of which is easily destroyed when 

 damage is inflicted. 



The thickness of the ghost membrane has been measured by 

 numerous investigators with a wide variety of results ranging from 

 15 to 700 vafx (Jung, 1950). This seems rather embarrassing. But when 

 the methods used for the measurements are considered the results can 

 be classified into two groups, viz. those obtained from dried ghosts 

 (electron microscope. Fig. 135, p. 272, Wolpers, 1941; leptoscope^ 

 Waugh, 1950), yielding 15-25 m^, and those from hydrated ghosts 

 (dark field observation, Lepeschkin, 1927; micrurgy, Seifriz, 1927) 

 with about 500 m/<. The last figure has also been found by Mitchison 

 (1950b), who has thrown down the ghosts by a centrifugal force of 

 1 10,000 g to a compact mass which is still 5 5 % of the volume of the 

 intact red cell. From this result it follows that the swollen membrane 

 is as thick as half the depth of the erythrocyte (diameter c-d of Fig. 

 132) and that it shrinks when dried to 1/25 of this size! The inner 

 part of the membrane, therefore, represents in vivo a very loose gel 

 with only 4% protein, which fills almost the whole erythrocyte. 



