Abstract

All clinical anthelmintics are markedly toxic to earthworms. This simple test may therefore be used for determining whether a given substance has any anthelmintic properties. It may also be used to determine the relative activity of different samples of a given drug. It could not be used to compare the clinical value of different anthelmintics, since this often involves factors other than simple vermicidal efficiency; such, for instance, as absorption, local and general toxicity, etc. For instance the highest vermicidal efficiency is possessed by substitutes that are not clinically available for this purpose; viz., mercuric chlorid, cupric sulphate, and mustard oil.

Aspidium, chenopodium, pelletierin, thymol, betanaphthol, and chloroform are highly effective. So is santonin in the presence of an appropriate solvent (bile-salts and sodium bicarbonate, simulating the intestinal fluid).

Somewhat less effective, but still quite toxic are kamala, kousso, and granatum. Spigelia is rather feeble.

Fresh (germinable) pumpkin seed and squash seed are quite highly efficient, the active principle being soluble in water and destroyed by boiling. In view of their cheapness, availability, and presumably low toxicity to men, renewed clinical interest in these is indicated.

Spices and "sharp" substances including mustard, pepper, onion and cantharidin are quite toxic. Their use in the preparatory treatment is therefore well justified (except of course cantharidin). Indeed, pepper potentiates or synergizes the effects of the more active anthelmintics.

Mixtures of the active anthelmintics give simple summation of efficiency. This may be useful for decreasing their toxic effects on the hosts. It would need to be determined by further animal experiments and clinical trial.

Oleoresin of aspidium appears to be quite stable, although the dry rhizome deteriorates. Different samples agree fairly in activity. The deposit that occurs in some oleoresins appears to have little if any influence in the activity.

Different samples of pelletierin tannate are also of fairly uniform activity. The "pelletierine tanret" is a secret preparation without any advantage.

Most substances that are toxic to earthworms produce a primary irritation or agitation, that results in the withdrawal of the worm from the neighborhood of the poison. This is observed with santonin, but is no more marked with this than with other anthelmintics.

By virtue of this effect, anthelmintics doubtless often "expel" the parasite when the concentration does not rise sufficiently high to kill the worm.