BIOLOGICAL PAPERS. 201 



Finally, seeds are projected by hygroscopicity, causing the explo- 

 sive action of the capsules. Certain fruits, which have warped or 

 dried unequally, will burst suddenly and scatter the seeds. Many ex- 

 amples of this are found, as the common blue violet, the pansy, balsam, 

 witch-hazel, cranesbill, and herb-robert ; the last two being species 

 of geranium, whose ovaries separate when ripe into five carpels^ 

 which split off from below upwards, from a long central axis, throw- 

 ing the seeds at times a distance of ten feet. "The capsule of the 

 South American sand-box tree bursts open when thoroughly dry 

 with a noise like that of a pistol-shot."'^ There is said to be a plant 

 in Canada whose capsule when bursting pops like a gun. 



But seeds are also covered with a coriaceous pod beset with prickly 

 points, in order to prevent their being eaten by animals. Examples 

 are species of Castanea {cheBtnut and chinquapin) and the y^sculus 

 (horse-chestnut or buckeye). The seeds of the latter contain a bitter 

 narcotic principle which renders the otherwise farinaceous interior 

 more or less noxious. Those of the ^sculus pavia ( Red buckeye ) 

 are used to stupefy fish, especially by the colored people of the South. 

 The root of the plant is said to be used as a substitute for soap. 



After the seeds have been disseminated it is necessary that a cer- 

 tain time elapse before they will germinate. The vegetable kingdom 

 has been likened unto the fall and redemption of man. As it is 

 necessary that our bodies remain in the grave until the last resurrec- 

 tion, so with seeds there must be a time of rest before the process of 

 germination commences. 



On the other hand, seeds do not retain their vitality ad infinitum 

 There is great diversity along this line. Some perish almost immedi- 

 ately after they are disseminated if they are not planted at once, while 

 others have been known to germinate when fifty or sixty years old, 

 and it is claimed by some that seeds that have been buried several 

 feet beneath the surface of the earth for many hundred years have 

 sprouted when planted, but this is considered not well established.^ 



Germination has been defined ^ as "the process by which an em- 

 bryo unfolds its parts," and "is complete when the plantlet can lead 

 an independent existence." There are, therefore, "two stages in the 

 process of germination : (1) That marked by the protusion of the 

 first rootlet; (2) the subsequent development of the embryo into an 

 independent plant." 



Dr. J. M. Coulter says: "This 'awakening" of the seed is spoken 

 of as its 'germination', but this must not be confused with the germi- 

 nation of a spore, which is real germination. In the case of the seed 



5. Bergen's Elements of Botany, p. 191. 



6. Gray's Structural Botany, p. 328. 



7. Goodale, Physiological Botany, p. 462. 



