LUMINOUS ORGANS AND LIGHT OF THE PENNATULiE. 253 



them, perhaps, all the polyps, into the category of animals, 

 the nervous functions of which are not confided to special 

 histological elements. 



After having spoken at length in the memoir of the 

 different means of excitation capable of exciting luminous 

 phenomena in the polyps and the zooids, we must now 

 determine what action the same agents can produce on 

 the luminous matter after its separation from the polyps, 

 insisting more particularly on the power which soft water 

 exercises on the luminous matter, be it of the Pennatulidse or 

 be it of other animals, which will be cited further on. We 

 arrive, then, at the following conclusions : — The luminous 

 matter of the Pennatulse may be directly induced to shine 

 when detached from the polyp or the zooid, by a shock, by 

 rubbing, by soft water, by an electric current, and by heat- 

 ing, not only directly after it has been extracted from living 

 polyps, but also after their decomposition. The memoir 

 goes on to, treat of the action of electricity, of heat, of 

 light on the phosphorence of the Pennatulte, and speaks also 

 of the spectral analysis of this light. We will terminate this 

 summary by giving various other conclusions from the 

 memoir, which are the following : — Admitting what has been 

 demonstrated upon another occasion — that is to say, that the 

 phosphorence of fatty substances is a phenomenon which 

 accompanies their slow oxidation, it appears very probable 

 that the light of the Pennatulae accompanies the oxidation of 

 the fatty matter of the luminous cords. By the same reason 

 that, in the Torpedo, the electro-motive power of the 

 elements of the electric organs comes from the action of the 

 will or the artificial excitation of the nerves, and in the same 

 way that by the action of the nerves the intensity of the 

 oxidation and the development of the heat can be augmented 

 or diminished in a warm-blooded vertebrate, it may be sup- 

 posed that the nerves of the Pennatulae, or the elements which 

 stand in their place, are capable of producing in the luminous 

 batteries of the polyps and the zooids a momentary oxidation 

 more rapid and more intense, accompanied with a manifesta- 

 tion of light. 



The photogenic substance of the Penatules presents, in 

 the whole of its characteristics, the greatest resemblance with 

 the fatty matter contained in the cells of the epithelium of 

 the phosphorent Medusae, as also with those which I found 

 in the Beroides, and the Pholaides, and the Chetopters, the 

 Nocotolases sketched by Quatrefages. These matters react 

 on the different excitements and behave as if there was in 

 them a substance which rendered them phosphoric, and 



