152 Dr Robert E, Brown on the 



inorganic condition. They also, as in the case of plants, give rise 

 to many lesser circles of motion during their lifetime, by the several 

 substances of which they are composed being in a constant state of 

 change, and passing through the stages of assimilation, of perfect 

 vitalization, of death and separation from them, of decomposition, of 

 organization by plants, and of reassimilation by animals. In the 

 states of sleep and waking, it seems to me not unlikely that there 

 may be found to be an alternately preponderating action of the vital 

 and of the chemical forces analogous to that which we mentioned 

 as taking place in plants, under the influence and in the absence 

 of sunlight, and giving rise to some of the above-mentioned ac- 

 tions. Animal beings have much the same relation to vege- 

 table existences which these last bear to the inorganic matter 

 upon which the forces of vegetable life act. For as vegetable mat- 

 ter is derived from inorganic matter, so animal matter proceeds, for 

 the most part, from that which is vegetable. When matter, there- 

 fore, becomes animalised, it advances a step further from its original 

 chemical and mechanical condition, and extends the circumference 

 of that circle in which we have already seen the molecules of organ- 

 isable matter proceeding. It is no part of our present subject to en- 

 ter fully into a history of the many stages through which matter 

 passes in moving in this round. I therefore speak of the pas- 

 sage of matter from an inorganic state to one in which it is subject 

 to vital influences : — .of the passage of vegetable matter into that 

 which is animal, and of the descent of this last to its original 

 inorganic state, as if each were a single step ; whilst the truth is, 

 that between these stages, the matter in question passes through a 

 series of minor changes and combinations. Thus, if we trace the 

 progress of a portion of carbon from the mineral or inorganic state 

 in which it exists in carbonic acid, through some plant which it is 

 destined to feed, we may possibly find it performing a part succes- 

 sively in the composition of oxalic acid, of malic or tartaric acid, of 

 sugar or starch, and of albumen.* Again, between each of these 

 stages, if our knowledge were so far extended, we would probably 

 find it in an indefinite number of other conditions. For, from its 

 first entrance into the structure of a plant, to its passage into an 

 animal body, or its resolution into its first inorganic condition, it is 

 in that constant motion and state of perpetual change which charac- 

 terise matter under the influence of vitality. 



Besides the motions which have been noticed, there are many 

 others which occur upon the earth, either naturally, or which are 

 produced by art. The chief of these depend upon the forces of heat 

 and light, derived 'rem terrestrial sources, of electricity, galvanism, 

 magnetism, and the like, and upon the nervous force of animals. 



* Outlines of Chemistry, by Dr Gregory, 1st edit., p. 557. 



