ANIMALS AND PLANTS. 135 



ual changes which the contents of the plants pass through in the 

 formation of their spores, and then he doubled the proofs by 

 tracing the growth of these self-same spores into branching 

 plants. 



Subsequent researches have confirmed the observations of 

 Thuret, and have also carried that delicacy of distinction, which 

 he introduced, to the highest degree of critical comparison. 

 Moreover, it was in following out these elaborate examinations 

 that observers have come across some of the most important 

 physiological facts that this century has produced. 



One of these facts is this : that within the boundaries of a 

 simple circle, a series of phenomena are exhibited which consti- 

 tute the components of a whole life, of origin, growth, and 

 reproduction. The physiology of life, in this case, is reduced to, 

 or more properly speaking, it does not rise above the simplest 

 form of operation and manifestation. 



This I think you will fully comprehend from a description of 

 the life characters of one of the lowest organized of all plants. 

 It is closely related to, if not identical with, the famous " Red- 

 snow plant." In one of its states of existence it is frequently 

 to be found not only in water, but also in damp places ; and dur- 

 ing the winter, in some localities, it gives a red color to the snow 

 upon which it grows. The whole plant is a mere microscopic 

 globule, so small indeed that a single one would escape the eye, 

 but when congregated in vast numbers they make themselves 

 visible by their color. This little globe consists of a thick, trans- 

 parent, delicate shell or coat, (fig. 73, c,} which is filled with a red- 

 dish or brownish yellow granular mass (g, g l ). The latter is most 

 frequently found divided into two portions, (g; g- 1 ,) each one of 

 which contains a comparatively large brownish red globule, or 

 nucleus (n, n l ) as it is called. In this condition the plant is 

 known to be commencing a series of changes which result in its 

 total metamorphosis into new individuals. The manner in 

 which this is brought about is in this wise. When it is sub- 

 jected to the action of water, the transparent envelope (which 

 is the homologue of the stem of the thread-form aquatic plants, 



