The biological activity of phenolic compounds; the effect of surface active substances upon the penetration of hexyl resorcinol into Ascaris lumbricoides var. suls

The kinetics of the penetration of some representative anthelmintics and related compounds intoAscaris lumbricoidesvar.suis

1. The rate of penetration of some representative drugs intoAscaris lumbricoidesvar.suishas 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 ofAscarisis 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.

Nematode parasite populations in sheep on lowland farms IV. The effects of anthelmintic treatment

In the last twenty-five years, since it was realized that the control of flock infections was more important than the treatment of individuals with patent infections, there has been an increasing interest in the use of anthelmintic drugs. As might be expected there has been a wide search for the most effective chemicals and considerable research into the best methods of administration, and as a consequence of this many workers have been engaged in devising methods of testing the efficiency of various compounds.