Observations on limb development in Rana sylvatica following unilateral eye extirpation

1. The eye extirpation experiment ofDuRKEN (1913) has been repeated over a period of years with larvae ofRana sylvatica, and conflicting results have been obtained. 2. In the experiments herein reported, larvae have been reared under varied conditions of illumination and of temperature. The few defective cases obtained (0.7% of the whole) were distributed equally between the operated individuals and the controls, and were independent of the influences of darkness or of light, and of varying temperatures. 3. The results of these experiments strongly indicate that there is no causal relationship between the early removal of an eye and the later development of the limbs. 4. The occurrence of cases with defective limbs among museum specimens and among material collected in the field suggests that abnormal limb formation may be due to an instability of the individual.