184 CHEMLSTRY OF THE IMMUMTY REACTIONS 



also present in the various org-ans, and to greater or less extent in 

 the other body fluids, excepting usually the spinal fluid (Greer and 

 Beeht).®^ The place of their formation is unknown. Since bacteria 

 contained within a collodion sac implanted in an animal give rise to 

 the production of agglutinins, it is evident that the agglutinogens 

 are diffusible to some extent, at least, through collodion. Old cul- 

 tures of bacteria contain free agglutinogens, probably liberated from 

 disintegrated cells, and filtrates of such cultures will neutralize ag- 

 glutinins, showing both that the agglutinogens are filterable, and 

 that the reaction of agglutination is a eliemical one and not depend- 

 ent upon the presence of cells. Agglutinogens are said to pass 

 through dialyzing membranes, while agglutinins do not. So it is evi- 

 dent that the agglutinogen is of smaller molecular dimensions than 

 tlie agglutinin, just as toxin molecules are smaller than antitoxin 

 molecules. Agglutinogens are not destroyed by formalin, heat, or 

 ultraviolet rays in concentrations sufficient to kill the bacteria con- 

 taining them.*'^ Stuber holds that bacterial agglutinogens are lip- 

 ine.^*^' 



Properties of Agg'lutinins. — Like most of the other substances 

 produced in immunity, agglutinins are precipitated out of the serum 

 in the globulin fraction. All attempts to separate them from pro- 

 teins have been unsuccessful. Stark ^" found that trypsin does not 

 attack the agglutinins readily, corresponding to the resistance of the 

 serum globulins to this enzyme ; alkaline papayotin solution destroys 

 them slowly, while pepsin acts much more rapidly. Alkalies are de- 

 structive even when quite dilute, while acids are much less harmful. 

 The temperature resistance of agglutinins seems to be variable, 

 plague agglutinin being destroyed at 56°, while purified typhoid ag- 

 glutinin may resist 80°-90° ; most agglutinin serums lose their activ- 

 ity at 60°-65°. The rate of reaction of agglutinins increases with 

 the temperature, as long as this is not high enough to injure the 

 reacting substances."*' They are not precipitated by specific precip- 

 itins, but are readily absorbed by charcoal. They can be formed by 

 spleen tissue grown in artificial tissue cultures."*''^ 



The structure of the agglutinins (in the Elirlieh theory) is sim- 

 ilar to that of the toxin; /. e., there is a haptophore group by which 

 they combine with the agglutinogen, and a toxophore group by which 

 they produce the changes that cause agglutination. The agglutino- 

 gen is probably related to the antitoxins in structure, having a sin- 

 gle haptophore to unite w\\h tlie agglutinin. By degeneration of the 

 loxo])lior()us gi'oup of tlie agglutinin, agglntinolds nxay be formed. 



«3,Toiir. Infoct. Dia., 1910 (7), 127. 



04Stiissano and L<'niailc, Coiii))!. Kcnd. Acail. Sei.. 1011 {\'r2) . (S2?,. 



04a HioclKMii. Zoit.., li)16 (77), 388. 



05 Jnaufr. Dissert., Wiirzhurj,', lOOo. 



oclMadscn, ct nl.. Jonr. V.\\wv. Mod., 1900 (8), 337. 



con I'ly/gode, Wien. klin. Wocli., 1913 (20), 841. 



