144 .! F. MCCLEXDON. 



is composed of lecit-hin and cholestcrin with a little nucleo- 

 proteid. It is probable that these lipoids are chemically different 

 in different species of animals, since Lefmann 1 observed that the 

 lipoids of erythrocytes of the same species are not toxic-, whereas 

 those of another species may be very toxic. 



The distribution of these substances in the corpuscle has not 

 been ascertained. Pascucci 2 supposed the corpuscle to be a bag 

 of proteid impregnated with lecithin and cholesterin and filled 

 with haemoglobin. He found that artificial lecithin-cholesterin 

 membranes were made more permeable to haemoglobin by the 

 laking agents, saponin, solanin and tetanus or cobra poison. 

 Dantwitz and Landsteiner suppose the lecithin to be in com- 

 bination with protein. 



Hoppe-Seyler assumed the haemoglobin to be in combination 

 with lecithin in the corpuscle, and Bang 3 has shown that .lipoids 

 may lie fixed by haemoglobin. It seems evident that there does 

 not exist an aqueous solution of haemoglobin within the corpuscle, 

 since haemoglobin crystals may be made to form in Nectunis 

 corpuscles without extraction of water. Furthermore, Traube 

 and Goldenthal 4 find that haemoglobin has a haemolytic action, 

 and unless there exists some body within the corpuscle which 

 antagonizes this action (as serum does) a haemoglobin solution 

 could not be retained by the corpuscle. Probably all of the so- 

 called "stroma" constituents, not in combination with the hae- 

 moglobin, form the plasma membrane of the corpuscle. 



Under certain conditions, the haemoglobin comes out of tin- 

 corpuscles, and the blood is said to be laked. Laking of "fixed" 

 corpuscles occurs only after the removal of the fixing reagent. 

 Thus, sublimate-fixed corpuscles may be laked by substances 

 which combine with mercury, such as potassium iodide, sodium 

 hyposulphite or even serum proteids. The fact that they may be 

 laked by heating in water is probably because the nucleo-histone 

 is not fixed by sublimate. This process is prevented by hypertonic 

 NaCl solution, presumably on account of its power to precipitate 

 nucleo-histone (Stewart). Formaldehyde-fixed corpuscles m.i\ 



1 Beitrdge chem. Physiol. it. Path., XI., 255. 



2 Hofmeisler's Beilrdge, 1905. VI., 543, 552. 

 ' Ergeb. d. Physiol., 1907, VI., 152. 



4 Biochem. Zeit., 1908, X., 390. 



