Boll's phenomenon.
D000818:Animals; D001001:Anura; D005858:Germany; D006666:History of Medicine; D066298:In Vitro Techniques; D008027:Light; D009885:Ophthalmology / Q000266:history; D010783:Photometry; D010786:Photoreceptor Cells / Q000033:anatomy & histology; D012168:Retinal Pigments / Q000502:physiology*
D012168:Retinal Pigments