340 Analysis of Scientific Books and Memoirs. 



In this stage of the investigation having found, as I believed, a peculiar 

 character in the motions of the particles of pollen in water, it occurred to 

 me to appeal to this peculiarity as a test in certain families of cryptoga- 

 mous plants, namely Mosses, and the genus Equisetum, in which the exist- 

 ence of sexual organs had not been universally admitted. 



In the supposed stamina of both these families, namely, in the cylin- 

 drical anthene or pollen of Mosses, and on the surface of the four spathu- 

 late bodies surrounding the naked ovulum, as it may be considered, of 

 Equisetum, I found minute spherical particles, apparently of the same size 

 with the molecule described in Onagraria?, and having equally vivid mo- 

 tion on immersion in water; and this motion was still observable in speci- 

 mens both of Mosses and of Equiseta, which had been dried upwards of 

 one hundred years. 



The very unexpected fact of seeming vitality retained by these minute 

 particles so long after the death of the plant, would not perhaps have ma- 

 terially lessened my confidence in the supposed peculiarity. But I at the 

 same time observed, that on bruising the ovula or seeds of Equisetum, 

 which at first happened accidentally, I so greatly increased the number of 

 moving particles, that the source of the added quantity could not be 

 doubted. I found also that on bruising first the floral leaves of Mosses, 

 and then all other pirts of those plants, that I readily obtained similar 

 particles, not in equal quantity indeed, but equally in motion. My sup- 

 posed test of the male organ was therefore necessarily abandoned. 



Reflecting on all the facts with which I had now become acquainted, I 

 was disposed to believe that the minute spherical particles or molecules of 

 apparently uniform size, first seen in the advanced state of the pollen of 

 Onagraria?, and most other phsenogamous plants, — then in the antherae of 

 Mosses, and on the surface of the bodies regarded as the stamina of Equi- 

 setum, — and lastly, in bruised portions of other parts of the same plants, 

 were in reality the supposed constituent or elementary molecules of organic 

 bodies, first so considered by BufFon and Needhara, then by Wrisberg 

 with greater precision, soon after and still more particularly by Miiller, 

 and very recently by Dr Milne Edwards, who has revived the doctrine, 

 and supported it with much interesting detail. I now, therefore, expected 

 to find these molecules in all organic bodies : and, accordingly, on examin- 

 ing the various animal and vegetable tissues, whether living or dead, they 

 were always found to exist ; and merely by bruising these substances in 

 water, I never failed to disengage the molecules in sufficient numbers to 

 ascertain their apparent identity in size, form, and motion, with the smaller 

 particles of the grains of pollen. 



I examined also various products of organic bodies, particularly the gum 

 resins, and substances of vegetable origin, extending my inquiry even to 

 pit-coal ; and in all these bodies molecules were found in abundance. I 

 remark here also, partly as a caution to those who may hereafter engage 

 in the same inquiry, that the dust or soot deposited on all bodies in such 

 quantity, especially in London, is entirely composed of these molecules. 



One of the substances examined was a specimen of fossil wood, found 

 in Wiltshire oolite, in a state to burn with flame ; and as I found these 



