in Organic and Inorganic Bodies. S&7 



The results so obtained can only be regarded as approxima- 

 tions, on which perhaps, for an obvious reason, much reliance 

 will not be placed. From the number and degree of accord- 

 ance of my observations, however, I am upon the whole dispos- 

 ed to believe the simple molecule to be of uniform size, though, 

 as existing in various substances and examined in circumstances 

 more or less favourable, it is necessary to state that its diameter 

 appeared to vary from xj»oo5^^ ^® ao^icn^^ of an inch * 



I shall not at present enter into additional details, nor shall 

 I hazard any conjectures whatever respecting these molecules^ 

 which appear to be of such general existence in inorganic as 

 well as in organic bodies ; and it is only farther necessary to 

 mention the principal substances from which I have not been 

 able to obtain them. These are oil, resin, wax, and sulphur, 

 such of the metals as I could not reduce to that minute state of 

 division necessary for their separation, and finally, bodies so- 

 luble in water. 



In returning to the subject with which my investigation com- 

 menced, and which was indeed the only object I originally 

 had in view, I had still to examine into the probable mode of 

 action of the larger or peculiar particles of the pollen, which, 

 though in many cases diminished in number before the grain 

 could possibly have been applied to the stigma, and particularly 

 in Clarckia, the plant first examined, were yet in many other 

 plants found in less diminished proportion, and might in nearly 

 all cases be supposed to exist in sufficient quantity to form the 

 essential agents in the process of fecundation. 



I was now therefore to inquire, whether their action was con- 

 fined to the external organ, or whether it were possible to follow 

 them to the nucleus of the ovulum itself. My endeavours, how- 

 ever, to trace them through the tissue of the style in plants well 

 suited for this investigation, both from the size and form of the 

 particles, and the development of the female parts, particularly 

 Onagrariae, was not attended with success ; and neither in thi» 



" While this sheet was passing through the press, Mr DoUond, at my re- 

 quest, obligingly examined the supposed pollen of Equisetum vtrffotum with 

 his compound achromatic microscope, having in its focus a glass divided into 

 10,000ths of an inch, upon which the object was placed; and although the 

 greater number of particles or molecules seeij were about 29,^99, yet the 

 smaller did no exceed g5,i5gth of an inch. 



