. Phosphorescence; or, The emission of light by minerals, plants, and animals. y refer it plausibly enough to our electricalcondition.* I have given this account in Dr. Kane^s words,that the conditions under which this curious pro-duction of light occurred may be more readilyappreciated. The light arising from currying a horse, or rub-bing a cat^s back, has often been observed. A* See Dr. Kanes work, The Second Grrinell Expeditiou, etc. M 162 FHOSPBOEESCJENCi: IN peculiar snapping noise accompanies this liglit,wliicli is owing simply to the production of aquantity of electric sparks. Similar i
. Phosphorescence; or, The emission of light by minerals, plants, and animals. y refer it plausibly enough to our electricalcondition.* I have given this account in Dr. Kane^s words,that the conditions under which this curious pro-duction of light occurred may be more readilyappreciated. The light arising from currying a horse, or rub-bing a cat^s back, has often been observed. A* See Dr. Kanes work, The Second Grrinell Expeditiou, etc. M 162 FHOSPBOEESCJENCi: IN peculiar snapping noise accompanies this liglit,wliicli is owing simply to the production of aquantity of electric sparks. Similar instances ofspontaneous production of light have been observedon combing a woman^s hair^ provided it be verydry, and the atmosphere devoid of moisture.* Bartholin gives an account of a lady in Italy,whom he designates as ^^ mulier sjolendens/ whosebody shone with phosphoric radiations when slightlyrubbed with a piece of dry linen. A phenomenon, which might perhaps be termedsubjective jpliosplwrescencej occurs when injuries arereceived by the eye or the optic nerve (fig. 29).. Fig. Thus, when the head has been held down for somemoments, sparks are often seen before the eyeson resuming an upright position. These sparks * I have observed this frequently, but generally when a south-west wind is blowing, and the atmosphere higlily electrical. t Fig. 29, the human eye, showing the different membranesand the optic nerve. SUPJERIOR ANIMALS. 163 appear in motion, and are of frequent occurrencein some diseases, sucli as typlius fever, wlien tlieinvalid sees tliem upon tlie bed-cover, and con-stantly endeavours to pick them off with his?fingers. Wlien a blow is received upon the eye,an intense light is perceived : this must be familiarto pugilists. When the optic nerve is cut, no pain is felt; butan intense flash of light across the eyes is experi-enced. The same flash occurs when an electriccurrent passes through the optic nerve, as some-times happens when a piece of silver and a pie
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