Abstract
Retinal induction in the human eye was measured by the method of electro-stimulation to investigate its dependence on various properties of the inducing figure such as area, contour, configuration, angle, etc.
1. Direct induction by which a physiological effect remaining within the area pre-illuminated is meant depends little on the area of the retinal image unless it is too small.
2. The same is true for indirect induction set up simultaneously around a retinal image; for example, the indirect induction set up by a half-ring at its center was found much weaker than that set up by a broken ring of the same diameter, although the area illuminated was the same in the 2 cases.
3. Indirect induction becomes weaker as the distance from the margin of the inducing figure increases. The gradient of induction is, however, less steep when more than one inducing source are present (summation).
4. Angles contained in an inducing figure are an effective factor for producing indirect induction. This relation was illustrated by two examples.
