110 FERTILIZATION. 



important fticts which they have disclosed constitute a proud 

 triumph of their skill and sagacity over the most hidden opera- 

 tions of nature. 



194. The anther, in its early stage, together with the pollen, 

 forms a compact and moist body. ■ After the flower expands, 

 the anther matures ; the pollen absorbs the fluid from the cells 

 hning the anthers. These cells were proved by Purkinje to 

 consist of the fibrous cellular tissue, and this' tissue, when de- 

 prived of moisture, becomes exceedingly elastic, and the fibres 

 then act as springs in bursting the anther. Mirbel has clenion- 

 strated that, during the perfection of the pollen, the fluid of 

 this tissue is drawn by the endosmose of the pollen from h. 

 The presence of this fluid is necessary to the perfection of the 

 pollen, and it is equally necessary, that it should be drawn from 

 the fibrous tissue, that it may 2)erform its appropriate and neces- 

 sary function of bursting the anther. What a beautiful provi- 

 sion for insuring the due preparation of all parts, so that none 

 might be prematurely or tardily performed ! Under this or- 

 ganization, the anther cannot burst till the pollen has drawn 

 its perfecting nourishment. On the other hand, the pollen can- 

 not mature only by a means which insures its immediate escape 

 when perfected. 



195. During this preparation of the pollen, the pistil is 

 undergoing important changes. The stigmatic surface assumes 

 an irregular, granular appearance, becoming more lax in its 

 texture, and secreting a viscid fluid, all of which is accomplished 

 by the time the pollen is perfected. The pollen then falls upon 

 the stigma, is made to cohere by this viscidity, and moistened 

 by the secreted fluid. 



196. After the grains of pollen have remained upon the 

 moist stigmatic surface for several hours, the extine bursts at 

 one or more points, and through the apertures the intine is pro- 

 truded containing the contents of the pollen grain. These jyol- 

 len tubes penetrate the lax tissue of the stigma, and make their 

 way through the whole length of the style to the ovule, and 

 reach, and probably in all cases enter, the foramen. The re- 

 markable exhibitions of design for accomplishing this object 

 are unsurpassed by any phenomena in nature, and the researches 

 of Brown, Araici, Schleiden, and Brogniart have laid open a 

 field which cannot be viewed by a lover of nature with any 

 other feelings than those of unmingled delight. 



194. How is the pollen perfected ? What relation to the openinjsr of the 

 anther? — 195. What change is the pistil undergoing in tlie moan time ? — 

 196. What takes place w th the pollen grains ? 'What course do the pollen 

 tubes take ? 



