PHOSPHORESCENCE. 11 



poking Medusse into them. For such rash experiments, Ben Jonson's song might be 

 paraphrased — 



'" O do not -wanton with those eyes. 

 Lest you be sick with seeing," 



— and not bad advice either. 



In such Medusae as do sting, the power has been beUeved by Dicquemare, Eysenhardt, 

 and others who have practically looked to the subject, to reside in a mucus which can be 

 thrown off by the animal. Certainly such mucus, as I have often experienced, retains its 

 urticating properties for some time after being detached from its producer. If the view which 

 has been of late mentioned, that the filiferous capsules with their barbed projectiles are the 

 causes of the stinging sensation, the power of the mucus to sting does not contradict it, for 

 usually in it numbers of filiferous capsules may be perceived under the microscope. 



Phosphorescence. — Whatever doubt there may be about the stinging faculty of the 

 naked-eyed sea-jellies, there can be none about their capability of emitting light in the dark. 

 This wondrous power, possessed by comparatively few inhabitants of the air, is a gift bestowed 

 on many of the dwellers in the waters, and is especially possessed by creatures of the order 

 Radiata, as if, to use a fanciful analogy, their star-like forms had given them star-like 

 properties. The true polypes exhibit the phenomenon of phosphorescence in great perfection, 

 but as the majority of them are fixed, at least in their supposed most perfect condition, they 

 can play but little part in producing the luminosity in the sea, as seen by ordinary observers. 

 Many annelides and other articulata are phosphorescent, and even starfishes of the Ophiura 

 tribe, as has recently been shown by Quatrefages, but for similar reasons they are not likely 

 to be chief producers of the light. It is mainly by the Arachnodermata and minute animals 

 closely allied to them that the waves at night are — 



" Spangled with phosphoric fire 

 As though the lightnings there had spent their shafts, 

 And left the fragments glittering in the field."* 



The phenomenon of the luminosity of the sea was known to be produced by Medusse 

 as long ago as the time of Pliny,t and has attracted much attention in connexion with the 

 more ordinary species of Acalephse ever since. The first observations of importance on this 

 subject in modem times were those of the accurate Forskal, who described the phospho- 

 rescence of the Pelagia and ^^ quorea, ohserved by him during his voyage to Egypt, in 1762. 

 Since his time many voyagers and travelling naturalists, including Banks, Humboldt, Chamisso, 

 Peron, Lesueur, SpLx, Mertens, and Baird, have published valuable observations on this 

 interesting subject. On our own coasts, attention has been called to the subject, more 

 especially by Macculloch and Macartney. The valuable observations of Suriray in France 

 were chiefly confined to some minute animals allied to Medusse. In Germany, Tilesius and, 

 above all, Ehrenberg have published important and original essays on this subject ; and in 

 Italy, the experiments of the indefatigable Spallanzani still furnish some of our best modern 

 data. Many more authors might be cited who have treated the matter in greater or less detail, 



* James Montgomery, Pelican Island. Canto I. 

 t Hist. Nat., lib. xxxii, c. 10. 



