ON ACTIVE MOLECULES. 485 



appear to have suspected that particles having analogous 

 motions might exist in other organized bodies, and far less 

 in inorganic matter, I consider myself anticipated by this 

 acute observer only to the same extent as by Gleichen, and 

 in a much less degree than by Mliller, whose statements 

 have been already alluded to. — 



All the observers now mentioned have confined them- 

 selves to the examination of the particles of organic bodies. 

 In 18 19^ however, Mr. Bywater, of Liverpool, pubhshed an 

 account of Microscopical Observations, in which it is stated 

 that not only organic tissues, but also inorganic sub- 

 stances, consist of what he terms animated or irritable 

 particles. 



A second edition of this Essay appeared in 1828, proba- 

 bly altered in some points, but it may be supposed agree- 

 ing essentially in its statements with the edition of 1819, 

 which I have never seen, and of the existence of which I 

 was ignorant when I published my pamphlet. 



From the edition of 1828, which I have but lately met 

 with, it appears that Mr. Bywater employed a compound 

 microscope of the construction called Culpepper's, that the 

 object was examined in a bright sunshine, and the light 

 from the mirror thrown so obliquely on the stage as to give 

 a blue colom' to the infusion. 



The first experiment I here subjoin in his own words. [7 



" A small portion of flour must be placed on a slip of 

 glass, and mixed with a drop of water, then instantly ap- 

 plied to the microscope ; and if stirred and viewed by a 

 bright sun, as already described, it will appear evidently 

 filled with innumerable small linear bodies, writhing and 

 twisting about with extreme activity." 



Similar bodies, and equally in motion, were obtained 

 from animal and vegetable tissues, from vegetable mould, 

 from sandstone after being made red hot, from coal, ashes, 

 and other inorganic bodies. 



I believe that in thus stating the manner in which Mr. 

 Bywater's experiments were conducted, I have enabled 

 microscopical observers to judge of the extent and kind of 

 optical illusion to which he was liable, and of which he 



