30 LIFE AND DEATH. 



between the phenomena of the two orders to the 

 manner of their occurrence, seem to admit the com- 

 plete identity of the mechanisms. It is no longer 

 then in itself, individually, that the vital act is 

 particularized, but in the manner in which it is 

 linked to others. The vital order is a series of 

 physico-chemical acts realizing an ideal plan. 



Neo-vitalism has therefore assumed two forms, 

 one the more scientific and the other the more 

 philosophical. 



Chr. Bohr and HeidenJiain. Its scientific form was 

 given to it by Chr. Bohr, an able physiologist at 

 Copenhagen, and by Heidenhain, a professor at 

 Breslau, who was one of the lights of contemporary 

 German physiology. The course of their researches 

 led these two experimentalists, working independ- 

 ently, to submit to fresh investigation the ideas of 

 Lavoisier and those of Bichat, on the relation of 

 physico-chemical forces to the vital forces. 



It was by no means a question of a general 

 inquiry, deliberately instituted with the object of dis- 

 covering the part played respectively by physical and 

 physiological factors in the performance of the various 

 functions. Such an investigation would have taken 

 several generations to complete. No; the question 

 had only come up incidentally. Chr. Bohr had studied 

 with the utmost care the gaseous exchanges which 

 take place between the air and the blood in the lungs. 

 The gaseous mixture and the liquid blood are face 

 to face ; they are separated by thin membrane formed 

 of living cells. Will this membrane behave as an 

 inert membrane deprived of vitality, and therefore 

 obeying the physical laws of the diffusion of gases ? 

 Well ! no. It does not so behave. The most careful 



