{ 358 ) 



A Brief AccouiU of' Microscopical Observations made In the 

 Montlis of June, July, and August 1 827, on the Particles 

 contained in the Pollen of Plants ; and on the General 

 Emstence of active Molecules in Organic and Inorganic 

 Bodies, By Robert Brown, F.R.S, Hon. M.R.S.E. and 

 R. I. Acad., V. P. L. S. &c. &c. * ^ 



I HE observations, of which it is my object to give a summary 

 in the following pages, have all been made with a simple mi- 

 croscope, and indeed with one and the same lens, the focal 

 length of which is about ^\d of an inch+. 



The examination of the unimpregnated vegetable ovulum, 

 an account of which was published early in 1826 if, led me to 

 attend more minutely than T had done before to the structure 

 of the pollen, and to inquire into its mode of action on the p^s- 

 tillum in phaenogamous plants 



In the essay referred to, it was shown that the apex of the 

 nucleus of the ovulum, the point w^hich is universally the seat of 

 the future embryo, was very generally brought into contact 

 with the terminations of the probable channels of fecundation ; 

 these being either the surface of the placenta, the extremity of 

 the descending processes of the style, or more rarely, a part of 

 the surface of the umbilical cord. It also appeared, however, 

 from some of the facts noticed in the same essay, that there 



• This important and highly interesting Memoir was sent us by our friend 

 Mr Brown, and, although not published, we believe we are not acting con- 

 trary to the wishes of the author in giving it an early place in the Edinburgh 

 Philosophical Journal. 



f This double convex lens, which has been several years in my possession, 

 I obtained from Mr Bancks, optician in the Strand. After I had made con- 

 siderable progress in the inquiry, I explained the nature of my subject to Mr 

 DoUond, who obligingly made for me a simple pocket microscope, having 

 very delicate adjustment, and furnished with excellent lenses, two of which 

 are of much higher power than that above mentioned. To these I have often 

 had recourse, and with great advantage, in investigating several minute points. 

 But to give greater consistency to my statements, and to bring the subject as 

 much as possible within the reach of general observation, I continued to em- 

 ploy throughout the whole of the inquiry the same lens with which it was 

 commenced. 



X In the Botanical Appendix to Captain King's Voyages to Australia, 

 vol. ii. p. 534, et seq. 



