Part I. Specificity and Unitarianism in XIX Century Botany and Bacteriology: 1. The Unitarians
2. The Linnaeans
3. The dominance of specificity
4. The history of XIX century bacteriology from this point of view
Part II. The Inherited Controversy: Specificity and Unitarianism in Immunology: 5. Dichotomy and classification in the thought of Paul Erlich
6. Max von Gruber and Paul Erlich
7. Max von Gruber and Karl Landsteiner
8. Unity, simplicity, continuity: the philosophy of Ernst Mach
Part III. Chemical Affinity and Immune Specificity: The Argument in Chemical Terms: 9. Structural and physical chemistry in the late XIX century
10. Erlich's chemistry and its opponents: the dissociation theory of Arrhenius and Madsen
11. Erlich's chemistry and its opponents: the colloid theory of Landsteiner and Pauli
12. Erlich's chemistry and its opponents: the new structural chemistry of Landsteiner and Pick
13. The decline and persistence of Erlich's chemical theory
Part IV. Absolute Specificity in Blood Group Genetics: 14. Immunology and genetics in the early XX century
15. The specificity of cells and the specificity of proteins
16. The last confrontation
Conclusion.
