ENZYMES. 69 



the rennin again in an active form, from the combination of the rennin 

 with anti-rennin obtained by immunization by treatment with hydro- 

 chloric acid and then neutralizing. 



Recently a third manner of considering the toxin-antitoxin reaction 

 has been presented which is based on the fact that the reaction takes 

 place in a heterogeneous system. According to this the reaction is con- 

 sidered as an adsorption process, and in support of this assumption, sev- 

 eral examples can be given where finely divided solids or colloid sub- 

 stances take up toxins or enzymes, in an irreversible manner (NERNST, 1 

 BiLTz, 2 LANDSTEINER 3 ) . 



In reference to the formed antigens we must call attention to the fol- 

 lowing : 



If certain cells, for example, bacteria, blood-corpuscles, and sperma- 

 tozoa are injected into animals, then anti-bodies are formed which have 

 been called immune bodies (also amboceptors or sensibilizators) . By 

 themselves the immune bodies are inactive, but form with complements, 

 substances occurring in normal serum, so-called cytotoxins, which destroy 

 the kind of cells active in their formation. These cytotoxins are called 

 bacteriolysins, hamolysins, etc., according to the kind of cells used. 

 The immune bodies are specific in that they together with the com- 

 plement only attack those cells from which they are formed and 

 they are also stable against heat; the complements can act together 

 with different immune bodies and are very unstable, as they are gen- 

 erally destroyed by heating to 56 C. for one-half hour. Other anti- 

 bodies, produced under the influence of injected cells, show their action 

 by flocking together and agglutinating the cells set free in their forma- 

 tion. These anti-bodies are called agglutinins. 



In regard to the immune bodies, EHRLICH believes that they com- 

 bine with those cells under whose influence they have been formed 

 and also with the complements. They serve to fasten (amboceptors) 

 the complement, which produces the real poisonous action, to the cells. 

 The immune bodies correspond therefore to the haptophore groups of 

 the toxins and the complements of the toxophores. According to 

 BORDET the immune bodies act upon the cells in the way that the latter 

 are sensitive toward the complements (sensibilizators). 



If a certain immune serum is heated to 56 then, according to what 

 has been given, the complement is destroyed and the serum 'now con- 

 tains only the amboceptor of the original cyto-toxin and this amboceptor 

 can be made active again by the addition of normal serum (complement). 



1 Zeitschr. f. Elektrochem., 10, 379 (1904). 



2 Ber. d. d. Chem. Gesellsch., 37, 3147 (1904); Beitr. z. exp. Therapie, 1, 30 (1905). 



3 Zeitschr. f. Chem. u. Ind. d. Roll, 3, 221 (1907); Bioch. Zeitschr., 15, 33 (1908). 



