and on the Phosphorescence of Zoophytes. 119 



been written about it, more precise observations than we have 

 yet on record being required." IMr. Forbes does not mention 

 what this little is. I will endeavoui- to supply the deficiency. 

 The only references with which I am acquainted, as emanating 

 from British natm-alists, to the fact of the emission of phospho- 

 ric light by zoophjtes, relates to two species, Sej-tularia pumila 

 and Pennatula phosjjhorea. In Dr. Johnston's description of the 

 former, the following quotation from Stewart occm-s : — " This 

 species, and probably many others, in some particular states of 

 the atmosphere, gives out a phosphoric light in the dark. If a 

 leaf of the above Fucus {seiratus) with the Sertularia upon it re- 

 ceive a smart stroke \dth a stick in the dark, the whole coralline 

 is most beautifully illummated, every denticle seeming to be on 

 fii-e." 



This quotation is succeeded by some beautiful lines, the ap- 

 propriateness of which may excuse a repetition of them here. 



" While thus with pleasing wonder you inspect 

 Treasures the vulgar in their scorn reject, 

 See as they float along the entangled weeds 

 Slowly approach, upborne on bladdery heads; 

 Wait till they land, and you shall then behold 

 What fiery sparks these tangled fronds infold, — 

 Myriads of hving points ; the unaided eye 

 Can but the fire, and not the form descry." — Crabhe. 



"With regard to the second species, Pennatula phosphorea, the 

 knowledge of the existence of the phfenomenon of phospho- 

 rescence in it is sufficiently attested by the specific name, so that 

 it is unnecessary to adduce the testimony of those who make 

 mention of it. Such, it seems to me, was the extent of the know- 

 ledge of British natm-alists, so far as this can be ascertained by 

 reference to theii- writings (the only admissible evidence), of the 

 beautiful pheenomenon of the phosphorescence of zoophytes, up 

 to the time of the publication of my essay on Zoophytes in the 

 'Annals' for June, 1841, in which it was distinctly stated, that 

 all the transparent species, while in a living state, possessed phos- 

 phoric properties ; and I leave it to the )-eader to judge whether 

 this was sufficient to justify the assertion, that " the general fact" 

 of their phosphorescence had " long been known to British na- 

 turalists*" prior to that time. Mr. Forbes also seems to imply 

 that the general fact stands in need of more precise observations 

 than we have yet on record for it. 



I cannot but think that the papers alluded to in the beginning 



* The general fact of the phosphorescence of zoophytes may have been 

 known to continental naturalists prior to the publication of my essay. I am 

 not, however, sufficiently acquainted with their writings to assert positively 

 whether it was or was not to any or all of them. 



