THE LAW OF EMBKYOIS'IC DEYELOPMENT. Ill 



The stamens have, at the top, a sack, (the anther,) completely 

 filled with grains, (Fig. 2,) nicely packed; each of which proves on 

 examination to be a smaller sack, (the pollen,) filled with a viscous 

 fluid matter, in which is floating exceedingly small grains, called 

 fo villa. 



These are all essential organs in the re-production of plants, and 

 must perform their functions before the seed can be matured. We 

 may increase and multiply plants by layers, cuttings, budding, etc., 

 hut to re-produce a new plant, the agency of the stamens, pollen, 

 and fovilla, as well as of the seed, is needed. 



Under a good microscope this fovilla maybe seen in any ripe 

 pollen-grains, but the particles are among the most minute things 

 .we are called upon to examine, requiring the higher powers of the 

 instrument even to see them; and what seems truly wonderful, 

 these minute particles are found to have a proper motion of their 

 own. They move forward, backward, or side-ways, but never make 

 much progress in any direction; the motion appears to be object- 

 less, like that of an animal seeking food. 



The cause of this motion is not known; it is called molecular 

 motion, and may be the effect of some chemical action, but is more 

 probably due to the mysterious vital force. 



From the bottom of ponds of stagnant water, and [from spiingy 

 places, we may bring up plants so minute that no unaided human 

 eye has ever seen them; they consist of a single cell; they are the 

 smallest and the very lowest grade of plant-life, the Desmideoe, and 

 yet they are full-grown plants. They never grow to be anything 

 else; they are only Desmidece, and nothing more. They are true 

 plants, and not animals, as was once supposed. 



These minute, though full-grown plants, will be found actually 

 moving forward and backward and sidewise; making no progress; 

 appearing to have no aim, no object; precisely like the little par- 

 ticle of fovilla from the'pollen-grains of the highest orders of plants. 



Here, then, we have the first proof of the existence of the law in 

 the vegetable kingdom; the wonderful motion, both of the full- 

 grown plant of the lowest vegetable race, and of the particles, which 

 may be regarded as one of the first steps toward the reproduction 

 of the plants of the highest type. 



Arctic and Alpine travelers report the snow as sometimes red, 

 and we know that our stagnant waters are sometimes srreen. These 



