THE 



PHILOSOPHICAL MAGAZINE 



AND 



ANNALS OF PHILOSOPHY. 



[NEW SERIES.] 



SEPTEMBER 1829. 



XXIV. Additional Remarks on Active Molecules. % Robert 



Brown, F.R.S.,Hon. M.R.S.E. 4- R.I.Acad., V.P.L.S., Cor- 



respo7iding Member of the Royal Institutes of France and of 



the Netherlands, Sfc. Sfc* 

 A BOUT twelve months ago I printed an account of Mi- 

 -^ croscopical Observations made in the summer of 1827, on 

 the Particles contained in the Pollen of Plants ; and on the 

 general Existence of active Molecules in Organic and Inor- 

 ganic Bodies. 



In the present Supplement to that account, my objects are, 

 to explain and modify a few of its statements, to advert to 

 some of the remarks that have been made, either on the cor- 

 rectness or originality of the observations, and to the causes 

 that have been considered sufficient for the explanation of the 

 phaenomena. 



In the first place, I have to notice an erroneous asser- 

 tion of more than one writer, namely, that I have stated the 

 active Molecules to be animated. This mistake has probably 

 arisen from my having communicated the facts in the same 

 order in which they occurred, accompanied by the views 

 which presented themselves in the different stages of the in- 

 vestigation; and in one case, from my having adopted the 

 language, in referring to the opinion, of another inquirer into 

 the first branch of the subject. 



Although I endeavoured strictly to confine myself to the 

 statement of the facts observed, yet in speaking of the active 

 Molecules I have not been able, in all cases, to avoid the 

 introduction of hypothesis; for such is the supposition, that 

 the equally active particles of greater size, and frequently of 

 very diflcrent form, are primary compounds of these Molc- 



• Commimicatcd by the Author :— Mr. Hrowii's former paper on this 

 subject, will be fouiid in Phil. Mag. and Annals, N.S. vol.iv. p. 161. 



N.S. Vol.6. No. 33. Sept. 1829. Y cules, 



