98 PHYSICAL CHEMISTRY 



The permeability of erythrocytes seems to be similar to that 

 of plant cells according to the researches of Grijns (1896), 

 Hedin (1898) and others. Urea, however, seems to form an 

 exceptional solute to which the corpuscles are permeable. Ham- 

 burger (19 16 b) claims that the erythrocytes are permeable to 

 anions and to Na" and K*. . 



According to Rona and Michaelis (1909 b) the erythrocytes 

 of dogs and men are permeable to dextrose, judging from the 

 partition of dextrose between corpuscles and plasma (which was 

 not constant, however). On the contrary Kozawa (1914 b) 

 found the erythrocytes of swine, goat, sheep, horse, ox, cat, rab- 

 bit and guinea pig very poorly permeable to pentoses, pentites, 

 hexoses, hexites, methylated sugar, disaccharides, amino acids 

 and salts of organic and inorganic acids, and the erythrocytes 

 of men, apes and dogs, the same to all except monosaccharides. 



The permeability of other animal cells seems to be similar to 

 that of erythrocytes except in the case of certain cells of the 

 kidney, gut, connective tissue and smooth muscle, which are 

 .more permeable. According to Meigs (1912 c) smooth muscle 

 cells have no plasma membranes. The composition of other cells 

 in regard to salts is similar to that of the erythrocytes, the Na 

 content of all the cells is less than that of the blood plasma. 

 Whereas the K content of the blood plasma is about .026 per cent, 

 that of the heart is .161, liver .1718, kidney .1643, spleen .1691, 

 brain .245, lung .0836, muscle .3, and that of erythrocytes .5 

 per cent. ' i : 1 '^^1 



The convoluted tubule cells of the kidney are permeable to 

 many dyes that do not stain other cells. According to Siebeck 

 (1912) they are more permeable to KC1 than to other salts. 



As is well known, phagocytes can take up solid objects, and 

 might include some fluid containing dissolved substances along 

 with them. The "pyrrol" cells of the connective tissue are con- 

 sidered by Evans and Schuleman (1914) to take up colloidal 

 dyes "phagocytically" but just what is meant is not clear. The 

 Kupfer cells of the liver also take up these dyes, and J. Voigt 

 (1914) claims that they take up colloidal silver. The reticulum 

 cells of the spleen and interstitial cells of the testicle behave 

 similarly toward these dyes. 



The eggs of some marine (Fundulus), migratory (smelt) and 



