SIMULTANEOUS INTERNAL AND EXTERNAL STIMULATION OF THE IRIS BY ADRENIN

Abstract

The reactions of the iris, denervated by removal of the superior cervical sympathetic ganglia, to adrenalin instilled in the conjunctival sac and to emotional excitement were studied in cats. Adrenalin begins to produce a marked dilatation of the corresponding pupil only about 15 days after the denervation. As time passes this dilatation occurs earlier, is more marked, and lasts longer. Emotional excitement produces stronger and longer pupillary widening of the previously instilled eye. On repetition of emotional excitement the effects increase. These reactions occur even 3-8 hrs. after the instillation, when both pupila are apparently in identical condition. Inactivation of the adrenals greatly diminishes, but does not wholly suppress, the above-mentioned results.