314 Mr Brown's Additional Remarks 



Aet. XV. — Additional Remarks on Active Molecules. By 

 Robert Bkown, F. R. S. 



About twelve months ago I printed an account of Micro- 

 scopical Observations made in the summer of 1827, on the Par- 

 ticles contained in the Pollen of Plants ; and on the general 

 Existence of active Molecules in Organic and Inorganic 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 

 phenomena. 



In the first place, I have to notice aa erroneous assertion 

 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 o^jMirred, accompanied by the views which present- 

 ed themselves in the different stages of the investigation ; 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 in- 

 troduction of hypothesis ; for such is the supposition, that the 

 equally active particles of greater size, and frequently of very 

 different form, are primary compounds of these Molecules, — 

 a supposition which, though professedly conjectural, I regret 

 having so much insisted on, especially as it may seem connect- 

 ed with the opinion of the absolute identity of the Molecules, 

 from whatever source derived. 



On this latter subject, the only two points that I endeavour- 

 ed to ascertain, were their size and figure : and although I 

 was, upon t1ie whole, inclined to think that in these respects 

 the Molecules were similar from whatever substances obtained, 

 yet the evidence then adduced in support of the supposition 

 was far from satisfactory ; and I may add, that I am still less 



