400 APPENDIX. NOTES. 



cules, when placed in a fluid medium, would move about 



in various directions, but by what cause these motions 



were generated he offers no conjecture. He very kindly 



shewed me this singular phenomenon, if my memory does 



not deceive me, with respect to some mineral substances. 



Mr. Brown has observed that the motions in question, he 



was satisfied, arose neither from currents in the fluid, nor 



from its gradual evaporation, but belonged to the particle 



itself; 1 and of the spherical molecules mixed with the other 



oblong particles obtained from Clarckia pulchella, that 



they were in rapid oscillatory motion: 2 in both mineral, 3 



vegetable, 4 and animal substances, 5 along with the mole- 



cules, he found other corpuscles, like short fibres some- 



what moniliform, or having transverse contractions, corres- 



ponding in number, as he conjectured, with that of the 



molecules composing them: and these fibrils, when not 



consisting of a greater number than four or five molecules, 



exhibited motion resembling that of the mineral fibrils, 



while longer ones of the same apparent diameter were at 



rest. 6 It does not appear clearly from the words of the 



learned author, whether the motion of the mineral mole- 



cules was similar to that of the vegetable ones, which he 



describes as oscillatory. The motions of the mineral fibrils, 



when not composed of more than two or three molecules, 



were at least as vivid as those of the simple molecule, and 



which from the fibril often changing its position in the 



fluid, and from its occasional bending, might be said to 



be somewhat vermicular; 7 now vermicular movement is 



a kind of progressive oscillation, the anterior extremity 



going from side to side and being followed by the body. 



1 Brief Account of Microscopical Observations, fyc. 4. 



2 Ibid. 5, 6. 3 Ibid. 10. 4 Ibid. 11. 5 

 6 Ibid. comp. 10, 11. 7 Ibid. 10, 



