378 APPEARANCES OBSERVED IN THE 



Frequently also, some were observed to be in the fluid, or 

 on its surface, for a long time motionless, but very brilliant ; 

 then they would give a few slight twinkles, seem to turn round, 

 and almost disappear ; then resume their original situation for 

 a moment, appear more brilliant than at first, partly disappear 

 again, and again return, and so on, for a number of times, till 

 at length they would disappear entirely ; but, after a time, per- 

 haps five or ten minutes j shew themselves in the same spot as 

 before These observations could be made only on the larger 

 spicula ; the minute ones being in incessant motion. 



On the first examination of this appearance, it seemed pro- 

 bable, that the motion might be communicated by animalcula 

 swimming through the fluid, and that these had been propaga- 

 ted after the death of the fish, as the eye was not quite fresh. 

 Soon afterwards, howe\ er, I examined the choroid in the same 

 way, from a flounder before it was quite dead. The same ap- 

 pearance presented itself, if possible still more lively ; and I 

 found also, that it continued in many of the spicula, after ex- 

 posure to the heat of boiling water. 



Since that period, I have observed the same phasnomena in 

 the choroid of all the fishes which I have examined, in the 

 cartilaginous as well as the bony. 



The motion continues, in a great many of the spicula even 

 after the fluid containing them has become putrid ; but it is 

 then more slow. The addition of ardent spirit deadens,, but 

 does not destroy the motion. After exposure to a heat of 

 boilino- water, the number of spicula seems much diminished, 

 and those which remain move less rapidly than before. The 

 addition of vinegar, in a quantity equal to the fluid containing 

 the spicula, suddenly causes a great diminution of the number 

 of moving ones, probably from coagulating the albuminous mat- 

 ter, which had been washed from the eye "along with the spi- 



cula^ 



