Penicillin Until 1957.- A. Introduction.- B. The Discovery of Penicillin.- C. Penicillin as a Chemotherapeutic Drug.- D. Early Studies on Mode of Action.- E. Paradoxical Inhibitory Zone Phenomena.- F. Morphological Changes in Bacteria.- G. Bacterial Lysis by Penicillin.- H. Interference of Penicillin with Nucleic Acid and Protein Synthesis?.- I. Park’s Nucleotides.- J. Penicillin Binding by Bacteria.- References.- The Role of Inducible DNA Repair in W-Reactivation and Related Phenomena.- A. Introduction.- B. Enzymatic Repair Systems in Bacteria and Their Viruses.- C. W-Reactivation and W-Mutagenesis.- D. Direct and Indirect Prophage Induction.- E. Plasmid Mediated UV-Protection and Mutagenesis.- F. Inducible “SOS”-Repair Functions.- References.- Biological and Biochemical Actions of Trichothecene Mycotoxins.- A. Introduction.- B. Trichothecene Structure and Genesis.- C. Detection of Trichothecenes.- D. Trichothecene Production.- E. Human and Animal Mycotoxicoses in which Trichothecenes are the Suspected Causative Agents.- F. Biological Activity of the Trichothecenes.- G. Biochemical Studies on the Action of Trichothecenes.- H. Physiological Mechanisms of Trichothecene Toxicity.- I. Metabolism of Trichothecenes.- J. Trichothecenes — Pharmaceuticals or Chemical Weapons.- References.- The Scrapie Agent: A Unique Self-Replicating Pathogen.- A. Introduction.- B. Biology.- C. Biochemical Characterization.- D. Theoretical Considerations for a Self-Regulated Protein Pathogen.- E. Future Directions.- References.- Non-Cholinesterase Effects of Anticholinesterases.- A. Background.- B. Neuropeptides.- C. Conclusion.- References.