12 Cuvier's Biographical Memoir ofM, de Lamarck, 



and the cause of all colours. When less condensed, and more 

 liable to escape, it is acidific fire (feu acidifique), the cause of 

 causticity when in great abundance, and of tastes and smells 

 when less so. At the moment when it disengages itself, and in 

 its transitory state of expansive motion, it is caloric fire. It is 

 in this form that it dilates, warms, liquefies, and volatilizes bo- 

 dies, by surrounding their molecules ; that it burns them, by 

 destroying tiheir aggregation ; and that it calcines or acidifies 

 them, by again becoming fixed in them. In the greatest force 

 of its expansion, it possesses the power of emitting light, which 

 is of a white, red, or violet-blue colour, according to the force 

 with which it acts ; and it is, therefore, the origin of the pris- 

 matic colours ; as also of the tints seen in the flame of candles. 

 Light, in its turn, has likewise the power of acting upon fire, 

 and it is thus that the sun continually produces new sources of 

 heat. Besides, all the compound substances observed on the 

 globe, are owing to the organic powers of beings endowed with 

 life, of which, consequently, it may be said, that they are not 

 conformable to nature, and are even opposed to it, because they 

 unceasingly reproduce what nature continually tends to de- 

 stroy. Vegetables form direct combinations of the elements ; 

 animals produce more complicated compounds, by combining 

 those formed by vegetables ; but there is in every living body a 

 power which tends to destroy it ; all, therefore, die, each in his 

 appointed season, and all mineral substances, and all inorganic 

 bodies whatsoever, are nothing but the remains of bodies which 

 once had life, and from which the more volatile principles have 

 been successively disengaged. The products of the most com- 

 plex animals are. calcareous substances, those of vegetables, soils, 

 or clays. Both of these pass into a siliceous state, by freeing 

 themselves more and more from their less fixed principles, and 

 at last are reduced to rock-crystal, which is earth in its greatest 

 purity. Salts, pyrites, metals, differ from other minerals only be- 

 cause certain circumstances have had the effect of accumulating 

 in them, in different proportions, a greater quantity of carbonic 

 or acidific fire. 



With respect to life, the only cause of all compositions, — the 

 mother, not only of animals and vegetables, but all bodies which 

 now occupy the surface of the earth, — M. de Lamarck yet ad- 



