INORGANIC AND LIVING BODIES 195 



Hence in both cases they are bodies composed essentially of two kinds 

 of parts, the one solid but supple and containing ; the other Hquid and 

 contained, but independent of the invisible fluids which penetrate and 

 develop within them. 



All these bodies possess individuaUty, either simple or compound ; 

 have a shape peculiar to their species ; are born at the moment 

 when Hfe begins to exist in them or when they are separated from 

 the body whence they spring ; are permanently or temporarily ani- 

 mated by a special force which stimulates their vital movements ; are 

 only preserved through nutrition which more or less restores their 

 losses of substance ; grow for a hmited period by internal development ; 

 form for themselves the compound substances of which they are made ; 

 reproduce and multiply so as to carry on the species hke themselves ; 

 lastly, all reach a period when the state of their organisation no longer 

 permits of the maintenance of life within them. 



Such are the faculties common to these two kinds of Uving bodies. 

 Let us now compare the general characters by which they are dis- 

 tinguished from each other. 



Comparison between the General Characters of Plants 



AND Animals. 



Plants are organised living bodies, not irritable in any of their parts, 

 incapable of performing sudden movements several times in succession, 

 and the vital movements of which are only performed by means of 

 external stimuli, that is to say, by an exciting cause provided by the 

 environment and acting chiefly on the contained and visible fluids 

 of these bodies. 



In animals, some or all of the parts are essentially irritable, and have 

 the faculty of performing sudden movements which may be repeated 

 several times in succession. The vital movements are in some per- 

 formed by means of external stimuli, and in others by a force develop- 

 ing within them. The external stimuli and internal stimulating 

 force affect the irritability of the parts, act upon the visible contained 

 fluids and give rise in all cases to the performance of vital movements. 



It is certain that no plant whatever has the faculty of suddenly 

 moving its external parts and repeating such movement several times 

 in succession. The only sudden movements that certain plants dis- 

 play are movements of relaxation or collapse of some part {v. p. 52) ; 

 hygrometric or pyrometric movements also are sometimes performed 

 by certain filaments when suddenly exposed to the air. As to the 

 other movements performed by the parts of plants, such as those 

 which make them bend towards the light, those which cause the 

 opening and closing of flowers, those which give rise to the erection 



