106 A TEXTBOOK OF PHYSIOLOGY 



owing to water being separated as ice in the process of freezing. 

 Electrical currents of high potential may also disintegrate the 

 corpuscles. 



Chemical. Many chemical bodies, such as arseniuretted hydrogen, 

 nitro-benzol, nitro-glycerine, nitrites, guaiacol, saponin, pyrogallol, 

 acetanilide, and ammonium salts, produce laking. Others, such as 

 sugar and sodium chloride, do not; these cannot permeate the corpus- 

 cular envelope. While urea and ammonium chloride permeate the 

 corpuscles readily, a solution of urea in isotonic solution of sodium 

 chloride does not lake the corpuscles, although ammonium chloride 

 does. A solution of ether in distilled water produces laking. It is 

 suggested that the permeability of the corpuscles is controlled by the 

 cholesterin and lecithin in the stroma as solvents of lecithin and 

 cholesterin produce laking for example, chloroform, ether, bile salts, 

 and amyl alcohol; but the majority of hsemolytic agents, both inor- 

 ganic and organic, are not solvents of these lipoids. 



Haemolysis by Foreign Sera. If a few drops of the blood of a 

 man be mixed with the serum of a rabbit in a test-tube, it will be found 

 that the solution, red and opaque to begin with, becomes after a time 

 transparent, showing that haemolysis has taken place. This property 

 is increased by immunizing the rabbit against the foreign red corpuscles. 

 The injection of a very small dose of foreign corpuscles is sufficient to 

 raise the haemolytic power of the serum. For example, 0-125 gramme 

 of ox blood, injected intravenously in the rabbit, produces a haemo- 

 lysin which specifically acts on ox corpuscles, so that rapid laking 

 takes place when the rabbit's serum is mixed with ox corpuscles but 

 not when mixed with any other animal's corpuscles. 



The explanation given for this phenomenon is the same as for bacteriolysis (see 

 p. 109). Sera, and especially imunized sera, have po.ver to destroy bacteria. There 

 are concerned two substances in the serum: (1) an amboceptor, which is increased by 

 immunization, and (2) a complement, which is present in fresh normal serum and is 

 destroyed by heating to 55 C. Very little is known as to the chemical properties or 

 mode of action of these bodies. The action takes place quickest at a little above body 

 temperature. If the ox corpuscles and rabbit's serum are mixed at C., there is no 

 haemolytic action, because the complement cannot act at this temperature, but tho 

 amboceptor combines with the corpuscles and can be removed with these from the 

 serum. After separation by the centrifuge the corpuscles can be washed in isotonic 

 salt solution, to remove all traces of the rabbit's serum, separated by the centrifuge 

 again, and then mixed with normal serum and warmed to body temperature. Lakini!; 

 then takes place because the complement alone is wanted to complete the reaction, and 

 this is present in any fresh normal serum. 



Hsemagglutinins, similar to the agglutinins which are produced to antagonize 

 bacteria, can also be obtained by the injection of foreign blood into an animal. These 

 cause the red corpuscles to run together, or agglutinate. Some sera contain no haemo- 

 lysins, only agglutinins; others contain hsemolysins and no agglutinins. The two 

 bodies, however, usually exist side by side, sometimes the action of one being more 

 marked, sometimes the action of the other. In agglutination the surface tension is 

 altered; the lecithin and cholesterin constituents of the stroma are supposed to take 

 a part. 



The haemolytic action of eel's serum is exceptional. If as little as O'l c.c. of eel's 

 serum per kilo of body weight is injected into a rabbit, it dies in two or three minutes. 

 This serum differs from other sera insomuch as heating to 54 C. destroys its action, 

 which is not restored by the addition of complement. 



