484 ADDITIONAL REMARKS 



letti cTultimo ordine included the active Molecules as well 

 as true Animalcules. 



I may next mention that Gleichen, the discoverer of the 

 motions of the Particles of the Pollen, also observed similar 

 motions in the particles of the ovulum of Zea Mays. 



Wrisberg and Miiller, Avho adopted in part Buffon's hy- 

 pothesis, state the glotgi^es, of Avhich they suppose all 

 organic bodies formed^ to be capable of motion ; and Miil- 

 ler distinguishes these moving organic globules from real 

 Animalcules, with which, he adds, they have been con- 

 founded by some very respectable observers. 



In 1814 Dr. James Drummond, of Belfast, pnbhshed in 

 the 7th volume of the Transactions of the Royal Society 

 of Edinburgh, a very valuable Paper, entitled " On certahi 

 Appearances observed in the Dissection of the Eyes of 

 Eishes." 



In this Essay, which I regret I was entirely unacquainted 

 with when I printed the account of my Observations, the 

 autlior gives an account of the very remarkable motions of 

 the spicula which form the silvery part of the choroid coat 

 of the eyes of fishes. 



These spicula were examined with a simple microscope, and 

 6] as opaque objects, a strong hght being thrown upon the 

 drop of Avater in which they Avere suspended. The appear- 

 ances are minutely described, and very ingenious reasoning 

 employed to show that, to account for the motions, the 

 least improbable conjecture is to suppose the spicula ani- 

 mated. 



As these bodies were seen by reflected and not by trans- 

 mitted light, a very correct idea of their actual motions 

 could hardly be obtained ; and with the low magnifying 

 powers necessarily employed with the instrument and in 

 the manner described, the more minute nearly spherical 

 particles or active Molecules which, when higher powers 

 were used, I have always found in abundance along with 

 the spicula, entirely escaped observation. 



Dr. Drummond's researches Avere strictly limited to the 

 spicula of the eyes and scales of fishes ; and as he does not 



