292 American Scientific Association. 



existence, and the fourth animal existence. Now it is apparently 

 impossible for any known force in nature to raise matter through 

 all these grades at once. On the contrary, there is a special force 

 adapted for the elevation of matter from each plane to the one above. 

 It is the special function of chemical affinity to raise matter from 

 plane one to plane two. All the changes too which take place 

 upon plane two by the mutual reaction of bodies situated upon 

 that plane, are under the guidance and control of this force. It 

 is the special prerogative of the force of vegetable life, to 

 lift matter from two to three, or from the condition of mineral 

 to the higher condition of vegetable matter. All the changes 

 which take place upon this plane, the laws of which constitute vege- 

 table physiology, are under the guidance of this force. Finally the 

 force of animal life, and that alone, enjoys the privilege of lifting 

 matter still higher into the fourth plane, i.e. the plane of animal 

 existence. No force in nature can lift from one to three, or from 

 two to four. Plants cannot feed entirely upon elementary mat- 

 ter, nor can animals feed upon mineral matter. The reason of this 

 will be seen in the sequel. Thus it seems that after matter is 

 raised from the elementary to the mineral condition, it requires an 

 additional force of another and peculiar kind to raise it into the 

 vegetable kingdom, and again another accession of force to raise it 

 into the animal kingdom. Thus these kingdoms are truly repre- 

 sented as successive planes raised one above the other thus : 1, 

 elements ; 2, mineral kingdom ; 3, vegetable kingdom ; 4, animal 

 kingdom. 



In the same manner as matter may be arranged in seve- 

 ral distinct and graduated kingdoms, it seems to me the forces 

 of nature may be properly divided into distinct groups ar- 

 ranged in a similar manner one above the other. These are the 

 physical, the chemical and the vital forces. And as in the case 

 of matter, so in the case of force it is impossible to pass directly 

 from the lowest to the highest group without passing through the 

 intermediate group. The conversion of physical into vital force 

 seems impossible without passing through the intermediate con- 

 dition of chemical force 



The argument of Mr. Le Conte went over wide ground and dis- 

 cussed the de- composition and re-formation of tissues and cells in 

 plants — the atomic changes — the conservative forces, showing that 

 vital is only transferred to physical force. In conclusion he asked ; 

 Ji If this is so, is it not possible that physical forces may generate 



