594 



this proportion was 1 to 8.5 and 1 to 12.5 respectively: while in an 

 analysis of leucocytes by Lilienfeld ^) the proportion was 1 to Ö.55, 

 and in an analysis of salmon sperm by Mieschek^) it was 1 to 8.6. 



In ordinary cells it is uncertain whether the lecithin and Cho- 

 lesterin are distributed uniformly through the protoplasm or are ac- 

 cumulated at the surface. E. Overton ^) draws attention to the prob- 

 ability that Cholesterin and lecithin play an important part in the 

 osmotic phenomena of cells in general and concludes that they may 

 preponderate at the surface of the cell. In the erythrocyte there are 

 strong grounds for believing that they are present wholly or chiefly 

 in the most superficial layer. That the surface film of the erythrocyte 

 has this chemical nature is shown by many of the reactions which 

 they exhibit when exposed to different conditions of temperature, sol- 

 vents etc. This was pointed out in 1892 by the author in the fol- 

 lowing passage'^): 



"The film or envelope is probably in large measure composed of 

 lecithin and Cholesterin and these are substances which possess many 

 of the physical properties of fats, although of a different chemical 

 composition. If we assume this to be its composition the running of 

 the red disks into rouleaux can readily be explained, since it has been 

 shown by Norris that disks of any material, e. g. cork, floating in a 

 fluid, tend in the same way to adhere in rouleaux, provided their sur- 

 faces are covered with a layer which is not wetted by the fluid" ^). 



The idea thus expressed was set forth in more detail in the edition 

 of Quain's Anatomy above referred to (1893, Vol. 1, p. 210): 



1) Zeitschr. f. physiol. Chemie, Bd. 18, 1894, p. 473. 



2) Arch. f. Pathol, u. Pharm., Bd. 37. 



3) Ueber die allgemeinen osmotischen Eigenschaften der Zelle etc. 

 Vierteljahrsschr. d. Naturforscher-Gesellsch. Zürich, 1899, p. 88. 



4) Essentials of Histology, 3. Edit., p, 16. 



5) This experiment by Norris, which has been disregarded by most 

 writers on the subject, is of prime importance in connection with the- 

 elucidation of the nature of the surface layer of the erythrocyte. Norris 

 took a number of cork disks and loaded them with pellets of lead in 

 such a manner that they were brought to the specific gravity of water 

 (or any other fluid it was desired to use). A number of such disks 

 placed in a beaker of water lie scattered about irregularly and with no 

 tendency to form rouleaux. But if their surfaces are previously coated 

 wath some materal which is not miscible with water, although the disks 

 swim about independently and irregular!}^ as long as the water is agitated, 

 when it comes to rest they adhere to one another in rouleaux, exactly 

 as do the red corpuscles of the blood. (Norris, Proc. R. Soc, Vol. 17, 

 1869, p. 434.) 



