Abstract
1. The retina of man was stimulated with exponentially rising currents of various time-constants, the index of excitation being the slightest possible light-sensation evoked by the current. Between the threshold referred to the rheobase and the time-constant of current rise, a linear relation was found for greater values of the time-constant, as predicted by Hill's theory, but against the theory, in some cases there was no initial curvature of the “accommodation” curve to be found.
2. The reciprocal of the slope of the curve was dependent upon the adaptation state of the eyes; the value of A lay between 17.5 and 25 m sec. for a moderate light adaptation, 35-90m sec. for the complete light adapta-tion and 45-320m sec. for the complete dark adaptation.
3. The value of λ, for the moderate light adaptation is smaller than that obtained by Soland at the ulnar nerve of man. This relation is hardly consistent with another evidence that the excitation process in the retina must be much slower than that in peripheral nerves. It was shown that this apparent contradiction is due to the periodical nature of excitation in the retina. The usual method for measurement of “accommodation” is applicable only to non-periodical systems like peripheral nerves under normal condition.
