THE KE-ACTIONS OF OEGANIC MATTER ON FOECES. 47 



increases the brilliancy of the light. Moreover, by separating 

 the luminous matter. Prof. Matteucci has shown that its 

 emission of light is accompanied by absorption of oxygen 

 and escape of carbonic acid. The phosphorescence 



of marine animals has been referred to other causes than 

 oxidation. In some cases, however, it is, I think, explicable, 

 wdthout assuming any m^ore special agency. Considering that 

 in creatures of tlie genus Noctiluca^ for example, to which the 

 phosphorescence most commonly seen on our own coasts is 

 due, there is no means of keeping up a constant circulation, 

 we may infer that the movements of aerated fluids through 

 their tissues, must be greatly affected by impulses received 

 from without. Hence it may be that the sparkles visible at 

 night when the waves break gently on the beach, or when an 

 oar is dipped into the water, are called forth from these 

 creatures by the concussion, not because of any unknown 

 influence it excites, but because, being propagated through 

 their delicate tissues, it produces a sudden movement of the 

 fluids and a sudden increase of chemical action. ISTeverthe- 

 less. in other phosphorescent animals inhabiting the sea, as 

 in the Pyrosoma and in certain Annelida^ light seems to be 

 really produced, not by direct re-action on the action of 

 oxygen, but by some indirect re-action involving a trans- 

 formation of force. 



§ 20. The re-distributions of matter in general, are accom- 

 panied by electrical disturbances; and there is abundant 

 evidence that electricity is generated during those re-distri- 

 butions that are ever taking place in organisms. Experi- 

 ments have shown ^^ that the skin and most of the internal 

 membranes are in opposite electrical states;" and also that 

 between different internal organs, as the liver and the stomach, 

 there are electrical contrasts — such contrasts being greatest 

 where the processes going on in the compared parts are most 

 unlike. It has been proved by M. du Bois-Eeymond that 

 when any point in the longitudinal section of a muscle is 



