PERMEABILITY OF ERYTHROCYTES. 



39 



to the substance in solution. Among those solutions in which the blood- 

 corpuscles are dissolved, independently of the degree of osmotic pres- 

 sure of the solution, urea occupies the first place. The ammonium 

 salts, with the exception of the sulphate, behave in the same manner. 

 Certain exceptions to which the laws of osmotic pressure for the blood- 

 corpuscles do not appear to apply H. Koeppe has been able to explain 

 according to the theory of solutions of van 't Hoff. The circumstance 

 must be taken into consideration, as Ostwald was the first to point out, 

 whether, in accordance with the concentration of their solution, the 

 dissolved substance has or has not completely dissociated itself into its 

 ions. 



Many agents separate the coloring-matter from the stroma. In 

 consequence the hemoglobin is dissolved in the blood-plasma, and the 

 blood becomes transparent, as it contains the coloring-matter in the 

 form of a transparent pigment. It is, therefore, designated lake- 

 colored. Lake-colored blood is dark red. In the dissolution of the 

 erythrocytes the change does not affect the aggregate condition, but it 

 consists only in a transposition of the hemoglobin, which leaves the 

 stroma and passes over into the blood-plasma. Therefore, no reduction 

 in temperature takes place. 



Method. For the microscopic demonstration of the stroma it is recommended 

 that a one per cent, solution of tartaric acid blood mixed with an equal volume 

 of concentrated sodium sulphate be carefully added. In order to obtain an 

 abundance of stroma for chemical examination, denbrinated blood is mixed with 10 

 volumes of a solution of sodium chlorid containing i volume of the concentrated 

 solution and from 1 5 to 20 volumes of water. In this the stromata are precipitated 

 as a whitish sediment. 



The following agents effect separation of stroma and hemoglobin: 



(a) Physical agents: (i) Heating of the blood to a temperature of 60 C. 

 The degree of heat differs, however, in different animals. (2) Repeated freez- 

 ing and thawing. (3) The static spark, although not after salts have been added 

 to the blood, and the constant and induced currents. 



(b) Chemically active substances generated within the body: (4) Bile or bile-salts. 

 (5) Serum from other species of animals. Thus, for instance, the serum of dogs' 

 blood and of frogs' blood dissolves the blood-corpuscles of the rabbit in a few 

 minutes. According to Rummo, Maragliano, and Castellino the blood-serum in 

 cases of acute infectious disease and chronic dyscrasias is said to be destructive 

 to the erythrocytes of healthy individuals. (6) Lake-colored blood from a number 

 of other species of animals. 



(c) Other chemical reagents: (7) Water. (8) Exposure to the vapors of 

 chloroform, ether, amylene; small amounts of alcohol, paraldehyd, thymol, 

 nitrobenzol, ethylic ether, acetone, petroleum ether, and others. (9) Antimony 

 hydrid, hydrogen arsenid, carbon disulphid. (10) Solutions of certain salts 

 may be mixed with blood in a definite concentration without causing change in 

 the red blood-corpuscles. If the saline solution is made either more dilute or 

 more concentrated, dissolution of the corpuscles takes place. This is the case, for 

 instance, with sodium chlorid. Traces of alkali render the erythrocytes more 

 resistant to such solutions, while traces of acid exert an injurious effect.' Accord- 

 ing to Bernstein and Becker salts cause an increase in the resistance to physical 

 solvents, but a reduction to chemical solvents. (n) Addition of boric acid, i 

 per cent., to amphibian blood causes the red mass, which at the same time sur- 

 rounds the nucleus when present and is designated zooid, to escape from the 

 stroma, which is designated ecoid, to withdraw from the periphery to the inte- 

 rior of the corpuscles, and often entirely to pass out. Briicker, therefore, consid- 

 ers the stroma to a certain degree a repository within which is lodged the remain- 

 ing substance of the blood-corpuscles especially endowed with vital phenomena. 

 (12) Strong acid solutions dissolve the blood-corpuscles, while weaker solutions 

 cause precipitates in the hemoglobin. This can be distinctly observed in the 

 case of carbolic acid. (13) Alkalies in moderate concentration cause sudden dis- 

 solution. Addition of potassic-hydrate solution of about 10 percent, to the blood 



