COMPARATIVE STUDIES ON PUPILLARY REACTION IN TETRAPODS

Abstract

Formol produces a constriction and then a very marked dilatation of the pupil in the pigeon. Curare produces a maximum dilatation of the pupil with abolition of the light reflex. Strophanthin and nicotin first constrict and then dilate the pupil. In other words, they stimulate and then paralyze the sphincter muscle. Spartein produces an evanescent dilatation and a subsequent constriction, and veratrin produces typical contracture of the iris musculature. This experiment shows that the iris muscle of the bird behaves essentially as any other striated muscle. The stimulation of the cervical sympathetic, the application of epinephrin or cocain did not change the size of the pupil.