410 Dr. J. H. Pring's Observations and 



appear that the same animal has been alluded to, but under a 

 different title. Thus, although, it must be confessed, imper- 

 fect in its details, no one can read the description given by 

 Macartney of the Medusa scifitillans, without recognizing its 

 full applicability, as far as it goes, to the subject of the present 

 notice. Two other instances, the Medusa hemispharica and 

 the Bero'e fulgens, are also described by Macartney as occa- 

 sionally to be met with in the British seas ; but their compa- 

 rative rarity has led this author himself to regard the minuter 

 example, of which we are now treating, as " the most frequent 

 source of the light of the sea around this country," and even 

 also " in other parts of the world." Passing, then, from these 

 general considerations as regards the animal itself, we shall 

 proceed to detail the various experiments to which it has V)een 

 subjected, which may be most conveniently treated of in the 

 following order, viz. — I, experiments subjecting the luminous 

 water to the action of galvanism ; 2, to the action of various 

 gases ; 3, to the action of the strong mineral acids ; 4, to the 

 action of aether and chloroform, &c. 



1. Effects of Galvanism and Electro magnetism. — Subjected 

 to a simple galvanic current from two of Smee's batteries, no 

 very perceptible effect could be observed to be produced. I 

 then attached an electro-magnetic coil to the batteries, and 

 thus passed the electro- magnetic current through the water 

 for some time: at first no very appreciable result appeared to 

 follow; but in a short time a steady and continued glow of 

 light was given out from the whole of the water, the surface 

 of which appeared further as if spangled with numberless 

 minute but persistent points of light. After a short time the 

 light began to grow more faint, and in a quarter of an hour 

 had ceased altogether, without the possibility of its being re- 

 produced, the loss of the light being evidently dependent upon 

 the death of the animalculae. 



2. Gases. Effects of Oxygen. — On filling a bottle with oxy- 

 gen gas, and allowing some of the gas to escape so as to be 

 replaced by a portion of the luminous sea-water, the phos- 

 phorescence of the Noctilucae contained in the latter could be 

 perceived to be sensibly increased when the water was agitated 

 with the oxygen, but no continuous or persistent glow of light 

 followed this experiment. For upwards of a week, however, 

 the little animals continued to live beneath this atmosphere of 

 oxygen, evidently emitting, on agitation, for several successive 

 nights during which the observations were continued, the same 

 tmount of increased light as had been observed to occur in 



he first instance. 

 Effects of Nitrogen. — Subjected to the influence of nitrogen, 



