EFFECT OF VARIOUS CONCENTRATIONS OF SODIUM FLUORIDE ON PARASITIC AND FREE-LIVING PROTOZOA AND ROTIFERA

¹ Department of Biology, Illinois Wesleyan University, Bloomington, Ill.

1. The LD50 (dosage from which 50 per cent of the animals die) of NaF for hamsters was found to be of the order of 70 to 80 mg. per kilogram of body weight.

2. Marked decrease in numbers of trichomonads (parasitic flagellated Protozoa) was observed in the cecum of hamsters following administration of 2 to 10,000 ppm NaF.

3. In vitro experiments in which trichomonads from the hamster were subjected to various concentrations of NaF (2 to 10,000 ppm) revealed specifically different behavior patterns in controls (distilled water) and 2 to 100 ppm NaF as opposed to 500 to 10,000 ppm NaF.

4. In vitro experiments in which free-living forms of Protozoa and Rotifera were subjected to various concentrations of NaF revealed the remarkable ability of these organisms to survive and reproduce when placed in concentrations of 2 to 1,000 ppm NaF. When placed in concentrations of 1,700 to 10,000 ppm NaF, these organisms were quickly killed.

5. A biological test is described in which Rotifera were employed as test organisms in differentiating between waters containing 10 or less ppm NaF and waters containing 20 or more ppm NaF.