The Relation Between Ionization and Toxicity to Insects for Some Neuropharmacological Compounds1

Abstract
In order to study the role of ionization in the toxicity of neural poisons to insects, the authors examine the toxicity of 35 neuropharmacological agents to five insect species and the mouse. On the hypothesis that only the unionized fraction is effective in the insect, but all is effective in the mouse, toxicity ratios, mouse: insect, are calculated and compared with the observed ratios. The results confirm the hypothesis for nitrogenous anticholinester-ases, and show clearly that convulsants are intrinsically ineffective against insects. With other agents, the factors are more complex.