ON ACTIVE MOLECULES. 477 



unfavorable to the opinion of the transmission of the particles 

 of the pollen to the ovulum, than to that which considers 

 the direct action of these particles as confined to the external 

 parts of the female organ. 



The observations, of which I have now given a brief 

 account, were made in the months of June, July, and 

 August, 1827. Those relating merely to the form and 

 motion of the peculiar particles of the pollen were stated, 

 and several of the objects shown, during these months, to 

 many of my friends, particularly to Messrs. Bauer and 

 Bicheno, Dr. Bostock, Dr. Fitton, Mr. E. Forster, Dr. Hen- 

 derson, Sir Everard Home, Captain Home, Dr. Horsfield, 

 Mr. Kcenig, M. Lagasca, Mr. Lindley, Dr. Maton, Mr. 

 Menzies, Dr. Prout, Mr. Renouard, Dr. Roget, Mr. Stokes, 

 and Dr. Wollaston ; and the general existence of the active 

 molecules in inorganic as well as organic bodies, their 

 apparent indestructibility by heat, and several of the facts 

 respecting the primary combinations of the molecules were 

 communicated to Dr. Wollaston and Mr. Stokes in the last 

 week of August. 



None of these gentlemen are here appealed to for the as 

 correctness of any of the statements made ; my sole ob- 

 ject in citing them being to prove from the period and 

 general extent of the communication, that my observations 

 were made within the dates given in the title of the present 

 summary. 



The facts ascertained respecting the motion of the par- 

 ticles of the pollen were never considered by me as wholly 

 original ; this motion having, as I knew, been obscurely 

 seen by Needham, and distinctly by Gleichen, who not 

 only observed the motion of the particles in water after the 

 bursting of the pollen, but in several cases marked their 

 change of place within the entire grain. He has not, how- 

 ever, given any satisfactory account either of the forms or 

 of the motions of these particles, and in some cases 

 appears to have confounded them with the elementary mole- 

 cule, whose existence he was not aware of. 



Before I engaged in the inquiry in 1827, I was ac- 

 quainted only with the abstract given by M. Adolphe 



