304 COLLOIDS IN BIOLOGY AND MEDICINE 



and on shrinking they take the shape of a thorn apple, and have 

 characteristic, pointed outgrowths. 



Their composition varies somewhat according to the species; a 

 beef's red blood corpuscle, besides salts, contains (according to E. 

 ABDEEHALDEN **) 



Per mile. 



Water 591.6 



Hemoglobin 316.7 



Albumin 64. 2 



Cholesterin 3.4 



Lecithin 3.7 



In an electric field they migrate to the anode (R. HOBER), and 

 though as a matter of fact, the electric charge varies according to the 

 species (KOZAWA), yet H. ISCOVESCO * 2 considers that only the cap- 

 sules and the stroma are electronegative, because intact blood cor- 

 puscles and stroma are precipitated by electropositive iron hydroxid 

 sol. The content on the contrary is electronegative, since corpuscles 

 dissolved in water are precipitated by arsenic sulphid hydrosol. 



The investigations on the lowering of the freezing point induced 

 by the contents of red blood corpuscles, etc., are exceptionally 

 numerous. These data will never lose their value. All conclusions 

 concerning the osmotic pressure of the respective solutions require a 

 revision in accordance with the investigation of W. BILTZ and A. 

 VON VEGESACK (see p. 46), who have shown that the presence of 

 colloids greatly influences the osmotic pressure of crystalloids (see 

 H. J. HAMBURGER and F. BUBANOVIC *) . It is established by the 

 investigation of R. HOBER that erythrocytes have a high internal 

 conductivity; this indicates that a considerable fraction of the salts 

 they contain are freely dissolved and do not occur in any organic 

 combination. 



As numerous as have been the studies of erythrocytes, just so 

 divergent are the ideas concerning their structure. Hitherto it has 

 been difficult to reconcile the demands of physical chemistry with 

 their other properties. By alternate freezing and thawing again, 

 hemolysis, i.e., exit of coloring matter may be induced; this be- 

 tokens a capsule which may be burst by a purely mechanical 

 effort exerted on the blood corpuscle in its entirety, thus giving exit 

 to the dissolved hemoglobin. This capsule must for the most part 

 consist of fatty colloidal particles (lecithin, cholesterin, or both), 

 since it may be removed by ether and other fat solvents, and may 

 even be melted at a temperature of from 60 to 65 C., thus allow- 

 ing the hemoglobin to escape. It must certainly contain lecithin 

 since pure cholesterin cannot be moistened by water and is totally 

 impermeable to it. Unfortunately, the properties of mixtures of 



