SPECIFICITY OF SERUM. 



229 



the others. The serums of the rabbits and pigeons 

 also agglutinated the homologous culture, but the 

 coagglutinins which they possessed did not affect 

 other strains equally. Consequently, it was sup- 

 posed that the cells of the three animals contained 

 a limited number of receptors in common,, whereas 



Fig. 6. Graphic representation of receptors of the second 

 order and of some substance uniting with one of them, c, 

 cell receptor of the second order ; d, toxophore or zymophor- 

 ous group of the receptor ; e, haptophore of the receptor ; f, 

 food substance or product of bacterial disintegration uniting 

 with the haptophore of the cell receptor. From Ehrlich's 

 "Schlussbetrachtungen," Nothnagel's System of Medicine, 

 vol. viii. 



other receptors which were present in one of the 

 animals were largely wanting in the other two. 



Inagglutinability was mentioned as a charac- 

 teristic of certain bacteria, especially the bacillus 

 of Friedlander. This condition is much more 

 important when it involves an organism which 



Ity of Some 

 Organisms. 



