506 . Additio7ial Remarks on 



that every marine animal which he has examined is luminous ; 

 and Mr. Baird, that in every instance where the water has been 

 properly examined when luminous, great quantities of ani- 

 malcules have been seen ; and that, on the contrary, where 

 the water has not been luminous, the animalcules have not 

 been present. 



Other causes have, however, been attributed for the appear- 

 ance by equally celebrated naturalists, although some of their 

 suppositions certainly do not appear very tenable. Martini 

 supposed the light to be occasioned by putrefaction ; Silber- 

 schlag believed it to be phosphoric ; Professor Mayer con- 

 jectured that the surface of the sea imbibed light, which it 

 afterwards discharged; Bajon and Gentil thought the light 

 electric, from a circumstance which the animalculists have too 

 greatly overlooked, viz. that it was excited by friction ; Forster 

 conceived that it was sometimes electric, sometimes caused by 

 putrefaction, and at others by the presence of living animals ; 

 Fougeroux de Bondaroy believed that it came sometimes from 

 electric fires, but more frequently from the putrefaction of 

 marine animals and plants. (Macartney in loc. cit.) The latter 

 opinion was also held by Commerson. M. Bory de St. Vin- 

 cent has more recently declared that marine animals take no 

 share in it ; and my friend, Daniel Sharpe, Esq., has par- 

 ticularly examined and described the luminous appearance of 

 the ocean during his recent passage to Lisbon. [Proc, ZooL 

 Soc, January, 1831.) The appearance here resembled a num- 

 ber of small sparks, not brighter than the smallest stars. 

 When a bucketful was taken up, nothing was visible until it 

 was shaken, when it was instantly filled with spangles, which 

 disappeared as the water settled. On carefully examining this 

 water with a microscope, nothing could be detected but an 

 abundance of small fibres and shreds of apparently animal 

 matter ; and Mr. Sharpe did not detect even one entire animal. 

 Hence he is disposed to infer that, in some cases at least, the 

 phosphorescence of the sea arises from the particles of dead 

 fishes, &c., always floating upon its surface, although he con- 

 fesses himself unable to explain the reason why these shine 

 only when the water is disturbed. 



From these and the preceding observations (for I am only 

 able to judge of the question from the statements of those 

 who have observed it), I certainly feel inclined to adopt the 

 opinion, that animalcules are not the primary cause of the 

 phenomenon ; in other words, that some species of luminosity 

 may and do exist without the presence of living animals. 

 How this effect is produced is a very distinct question. The 

 putrefaction of the waters of the ocean is not a likely cause ; 



