ON ACTIVE MOLECULES. 473 



often appearing to be flattened. Such oval particles were 

 found to be numerous and extremely active in white arsenic. 



As mineral bodies which had been fused containi.'d the 

 moving molecules as abundantly as those of alluvial de- 

 posits, 1 was desirous of ascertaining whether the mo])i]ity 

 of the particles existing in organic bodies was in any degree 

 afl'ected by the application of intense heat to the containing 

 substance. AVitli this view small portions of wood, botli 

 living and dead, linen, paper, cotton, wool, silk, hair, and 

 muscular fibres, were exposed to the flame of a candle or 

 burned in [)latina forceps, heated by the blowpipe; and in m 

 all these bodies so heated, quenched in water, and imme- 

 diately submitted to examination, the molecules were found, 

 and in as evident motion as those obtained from the same 

 substances before burning. 



In some of the vegetable bodies burned in this manner, 

 in addition to the simple molecules, primary combinations 

 of these were observed, consisting of fibrils having trans- 

 verse contractions, corresponding in number, as I conjec- 

 tured, with that of the molecules composing them ; and 

 those fibrils, when not consisting of a greater nuud)er than 

 four or five molecules, exhibited motion resembling in 

 kind and vivacity that of the mineral fibrils already de- 

 scribed, while longer fibrils of the same apparent diameter 

 were at rest. 



The substance found to yield these active fibrils in the 

 largest proi)ortion and in the most vivid motion was the 

 mucous coat interposed between the skin and muscles of 

 the haddock, especially after coagulation by heat. 



The fine powder produced on the under surface of the 

 fronds of several Ferns, particidarly of Jcrosfichum calo- 

 mclanos, and the species nearly related to it, was found 

 to be entirely composed of simi)le molecules and their 

 primary fibre-like compounds, both of them being evidently 

 in motion. 



There are three points of great importance wdiicli I was 

 anxious to ascertain respecting these molecules, namely, 

 their form, whether they are of uniform size, and their 

 absolute magnitude. 1 am not, however, entirely satisfied 



