TEMPORARY ABOLITION OF PHOTOTROPISM IN LIMAX AFTER FEEDING

When fed upon cooked potato the slug Limax maximus becomes for a day or more indifferent to light—its natural negative phototropism is suppressed. This effect is not produced by raw potato or other diets; it can be duplicated by injection of sugar solutions into the stomach or into the body fluids, and seems to be due to sugar absorbed during the digestion of the cooked starch. The fact is of interest particularly for the suggestion which it affords as to the explanation of fluctuations in conduct.