272 



FINE-STRUCTURE OF PROTOPLASM 



11 



The photographs of the residue of haemolysis (Fig. 155) merely 

 show a folded membrane. No inner structure is visible, which, ac- 

 cording to WoLPERS, proves the balloon theory of the structure of 

 erythrocytes. The average thickness of the membrane is 25 m/j,. 

 However, this measurement by Wolpers refers to the dried envelope 

 which has been reduced to 1/25 of its thickness in vivo. 



After suitable extraction of the lipid, Wolpers found the erythro- 





1 -. ■» "■ 



Fig. 135 Fig. 136 



Fig. 135. Membrane of red cells, osmotic tixation. Electron microscope 9500:1 (from 

 Wolpers, 1941). Fig. 136. Stretched membrane of red cell in electron microscope. 

 Image scale 51,000:1 (from Wolpers, 1941). 



cyte membrane to be porous. He therefore discards as improbable the 

 layer structure inferred from observations in the polarization micro- 

 scope. He also rejects the idea of a mosaic structure, which his electron 

 micrographs would at first sight seem to suggest; for he detected a 

 network structure in stretched erythrocyte membranes which had been 

 fixed with osmium tetroxide after extraction of the lipids (Fig. 136). 

 This induces him to believe that the stromatin has ^i frame structure, 

 in the meshes of which he imagines the lipids to be embedded. 

 Whether this opinion is shared, or the meshes are thought to be free 

 from lipids and filled with an aqueous phase, depends upon the re- 

 jection or acceptance of a superficial double film of lipid. However 

 this may be, the optically proved lamellar structure must not be 

 ignored; rather should an attempt be made to reconcile the two 

 findings. 



