308 ANNUAL OF SCIENTIFIC DISCOVERY. 



CAUSE OF PHOSPHORESCENCE IN THE OCEAN. 



WE derive the following from a paper read before the British As- 

 sociation by Dr. J. H. Pring, entitled " Observations and Experi- 

 ments on the Noctiluca miliaris, the Animalcular Source of the Phos- 

 phorescence of the British Seas." 



After glancing at the theories which have been proposed to explain 

 the phosphorescence of the ocean, and mentioning some remarkable 

 exhibitions of this phenomena, Dr. P. remarks, that there now "ap- 

 pears little doubt that the power of phosphorescence is actually pos- 

 sessed by animals ranking as high as the class of fishes." The 

 general phosphorescence of the ocean is chiefly due to the numerous 

 kinds of Medusae, Polypiferse, Rotiferse, and Infusoria, included un- 

 der the class Acalephse, but it is particularly owing to the microscopic 

 Noctiluca miliaris. Having taken a bucket of water from the sea, 

 Dr. Pring kept it over night, and on the following morning "innu- 

 merable very minute gelatinous bodies, of a globular form, could be 

 perceived even with the naked eye, floating near the surface of the 

 water." From repeated observations, it is clear that these little ani- 

 mals are either naturally specifically lighter than sea-water, or pos- 

 sess the power of rendering themselves so; this property appears 

 to be a living attribute, since it ceases at death. When examined 

 by the microscope, nothing is seen that indicates any special lu- 

 minous organ, but in several specimens a mass of loose flocculent 

 mucus was observed adhering near the insertion of the tentaculum, 

 "so that I am disposed to believe that the phosphorescent principle 

 resides in this mucus, and is probably most vivid at the moment of its 

 secretion, the secretion itself being influenced and thrown out more 

 abundantly under circumstances indicating danger." The natural 

 size of the animal is stated not to exceed the thousandth of an inch 

 in diameter. 



Dr. Pring performed some interesting experiments on this animal, 

 but we can only detail a few of them. Subjected to a simple galvanic 

 current from two of Smee's batteries, no very perceptible effect could 

 be observed. By passing the electro-magnetic current through the 

 water, after a considerable time a steady and continued glow of light 

 was given out from the whole of the water, the surface of which ap- 

 peared as if spangled with numberless minute but persistent points of 

 light. The light ceased after a quarter of an hour, and could not be 

 reproduced, owing evidently to the death of the animalcules. 



When a portion of the luminous sea-water was placed in a bottle 

 filled with oxygen gas, the phosphorescence of the animals was in- 

 creased whenever the water was agitated with the oxygen. The 

 animals lived in this state for more than a week. With nitrogen the 

 effect was similar, but the brilliancy of the light was somewhat less. 

 Sulphuretted hydrogen gas instantly destroyed all the luminosity, 

 being at once fatal to the animals. With carbonic acid gas the lu- 

 minous property of the water was not only brought out and highly 

 increased, but was rendered permanent for at least fifteen minutes, 

 the light being bright enough to enable one to see the hands of a 



