1. The rate of penetration of some representative drugs into Ascaris lumbricoides var. suis has been measured.2. The series of 4-n-alkyl resorcinols shows a typical homologous series effect.3. l-Nicotine penetrates relatively slowly.4. Its rate of penetration is greatly influenced by the extent of dissociation of its methyl pyrrolidine basic group.5. The rate of penetration of nicotine is greatly accelerated in the presence of some surface active substances.6. Chloroform is the most rapidly penetrating substance studied, and its penetration is not significantly influenced by the presence of proteins, carbohydrates and fats and their products of digestion.7. An analysis of the experimental results shows that the outermost layer of the cuticle of Ascaris is probably the main barrier to penetration. It behaves as if it were a thin; homogeneous layer of lipoid.8. The significance of these results in the study of anthelmintics is assessed.
SYNTHESIS AND PROPERTIES OF NON-IONIC SURFACE-ACTIVE SUBSTANCES BASED ON HEPTADECANOIC ACID AND PROPYLENE OXIDE
