480 ADDITIONAL REMARKS 



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 

 correctness or originality of the observations, and to the 

 causes that have been considered sufficient for the exphana- 

 tion of the phenomena. 



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

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

 active Molecules to be animated. This mistake has proba- 

 bly arisen from my having communicated the facts in the 

 same order in which they occmTcd, accompanied by the 

 views which presented 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 incpiirer 

 into the first branch of the subject. 



2] Although I endeavom'ed 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 different form, are primary compounds of these Mole- 

 cules, — a supposition which, though professedly conjectural, 

 I regret having so much insisted on, especially as it may 

 seem connected with the opinion of the absolute identity of 

 the Molecules, from whatever source derived. 



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

 voured to ascertain were their size and figure : and al- 

 though I was, upon the whole, inclined to think that in 

 these respects the Molecules were similar from whatever 

 substances obtained, yet the evidence then adduced in sup- 

 port of the supposition was far from satisfactory ; and I may 

 add, that I am still less satisfied now that such is the fact. 

 But even had the uniformity of the Molecules in those two 

 points been absolutely established, it did not necessarily 

 follow, nor have I anywhere stated, as has been imputed to 

 me, that they also agreed in all their other properties and 

 functions. 



I have remarked that certain substances, namely, sulphur, 

 resin, and wax, did not yield active particles, which, how- 



