146 EEPEODUCTION IN PLANTS AND ANIMALS. 



phenomena, what is it but the bursting forth of the pent- 

 up stream of vitality ? This display of its strength is 

 commensurate with its former manifestations of feebleness. 

 It is re-invigorated nature awakening from repose, and 

 offering her tribute of thankfulness to that beautiful star 

 the sun, during whose absence all nature mourns, at whose 

 coming all nature rejoices, whose many-colored rays dif- 

 fusive of life and beauty wherever they fall, are but pencil- 

 ings from the Eternal for our instruction. 



Every organized being, whether plant or animal, springs 

 invariably from an individual perfectly similar to itself, to 

 which it adheres during a space of time more or less long, 

 and from which it is finally separated at a definite period 

 under the form of a seed, spore, or ovum. The seed and 

 ovum, under envelopes more or less resisting, enclose a 

 germ. Within this germ all the organs of the adult animal 

 and plant exist in a rudimentary condition. Germination, 

 or the act by which these organs disentangle themselves 

 from their envelopes, does not increase their number, but 

 only augments their size and modifies their form. 



The development of the embryo within the ovum of the 

 animal and plant, takes place in pretty much the same 

 way. We have seen that vegetable fecundation consists in 

 the simple contact of the free extremity of the pollen tube 

 with the embijo sac of the ovule. It is then that the em- 

 bryo develops in the interior of the embryonic vesicle, and 

 it is interesting to follow the series of changes which take 

 place in this last organ. 



The embryonic vesicle is at first, simply a spherical cell, 

 developed at the end of the suspensory filament, filled with 

 fluid, and containing granular matter. A little time after 

 fecundation, a longitudinal septum, in the same direction as 

 the suspensor, is seen to form across the cavity of the cell. 



