0$ FRUITS. 117 



" Cross fertilization is effected, as every 

 one knows, by the action of the pollen of one 

 plant upon the stigma of another. The na- 

 ture of this action is highly curious. Pollen 

 consists of extremely minute hollow balls or 

 bodies; their cavity is filled with fluid, in 

 which swim particles of a figure varying from 

 spherical to oblong, and having an apparently 

 spontaneous motion* The stigma is compos- 

 ed of very lax tissue, the intercellular passages 

 of which have a greater diameter than the 

 moving particles of the pollen. 



" When a grain of pollen comes in contact 

 with the stigma, it bursts and discharges its 

 contents among the lax tissue upon which it 

 has fallen. The moving particles descend 

 through the tissue of the style, until one, or 

 sometimes more, of them finds its way, by 

 routes specially destined by nature for this 

 service, into a little opening in the integu- 

 ments of the ovulum or young seed. Once 

 deposited there, the particle swells, increases 

 gradually in size, separates into radicle and 

 cotyledons, and finally becomes the embryo, 

 that part which is to give birth, when the 

 seed is sown, to a new individual. 



