ANTIIOZOA ASTEROIDA. 151 



of all from the uppermost polypes. One remained phospho- 

 rescent for five minutes in spirits. 1 ' Interested with the 

 beauty of the phenomena, Professor Forbes induced his friend, 

 Dr. George Wilson, to enter on the inquiry into the cause of 

 the phosphorescence, and this distinguished chemist has fa- 

 voured me with the permission of publishing the result, which 

 I am happy to do in his own words. 



" The experiments recorded in the following statement 

 were conducted several years ago, and I have not been able to 

 recover the notes made at the period of their performance. I 

 was assisted in making them by a very accurate observer, Mr. 

 Swan, teacher of mathematics in this city, who is an excellent 

 electrician, and concurred with me in the conclusions I am 

 presently to state. As he had no bias in favour of the non- 

 electrical, rather than the electrical, view of animal phospho- 

 rescence, whereas, for reasons to be mentioned hereafter, I 

 considered the latter as not likely to prove the true one, his 

 opinion, as founded solely on the negative results of our expe- 

 riments, is of more value, so far as they are concerned, than 

 my own. 



" The experiments were undertaken at the request of our 

 friend, Professor Edward Forbes, in consequence of the curi- 

 ous observation he had made, that when the Pennatula is 

 struck or mechanically irritated, so as to cause it to phos- 

 phoresce, the light which shews itself, flows in a stream along 

 the body of the animal from the point struck towards the 

 plumed or fringed extremity, but not in the opposite direction. 

 This passage of light along the animal seemed so like the re- 

 sult of an electrical current flowing constantly in one direction, 

 that Mr. Forbes was anxious to have it ascertained whether 

 or not a development of electricity accompanied the evolu- 

 tion of light. 



" The form of the Pennatula rendered it more easy to make 

 experiments on this subject, than I suppose it would be with 

 many other phosphorescent animals. From Mr. Henry 

 Goodsir, then at Anstruther, I received two different supplies 

 of Pennatulse ; and on these the trials were made. Some of 

 them, as I understood from Mr. Forbes, were in full life, and 

 therefore in a fit condition for being employed in the inquiry. 



