258 EMBRYONIC DEVELOPMENT, SAME IN PLANTS AS ANIMALS. 



with seed after their kind, which when planted, swell and become 

 plants again. 



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

 filled with grains nicely packed, each of which proves on examina- 

 Fig.iis. tion to be a small sack (Fig. 115, the pollen) filled with a 

 viscous fluid matter, in which are floating exceedingly 

 small grains called fovilla. These are essential organs in 

 roiien. the reproductioil of the plailt? and must perform the j r 

 functions before the seed can be matured. We may increase and 

 multiply plants by layers, cuttings and budding ; but to reproduce 

 a new plant, the agency of the stamen, pollen and fovilla, is 

 needed as well as that of the seed. 



Under a good microscope, this fovilla may be 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 is truly wonderful, 

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

 own. They move forward, backward or sidewisc, but never make 

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

 less, not like that of an animal seeking its 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 pro!>;d>iv due 



From the bottom of ponds of stagnant water, and from springy 

 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 Desmideae ; 

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

 thing else, they are only Desmidese and nothing more. They are 

 true plants and not animals, as was once supposed. 



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

 moving forward and backward and sidewise ; making no progress ; 

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

 ticles 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 of the vegetable race, and of the par- 

 ticles, which may be regarded as one of the first steps toward the 

 reproduction of plants of the highest type. 



