IN THE ANIMAL ORGANISM. 211 



propagate the momentum of force in a living part, or 

 the effect which the active vital force inherent in the 

 part produces on all the surrounding parts, in all direc- 

 tions where- the force, or rather its momentum of mo- 

 tion, is consumed without resistance (for without motion 

 no change of matter occurs, and when motion has 

 begun, there is no longer resistance), an equilibrium is 

 obviously established in the* living part, between the 

 chemical forces and the remaining vital force ; which 

 equilibrium would not have occurred had not vital force 

 been expended in producing mechanical motion. 



In this state, any external cause capable of exerting 

 an influence on the form, structure, and composition of 

 the organ meets with no further resistance. If oxygen 

 were not conveyed to it, the organ would maintain its 

 condition, but without any manifestation of vitality. It 

 is only with the commencement of chemical action that 

 the change of matter, that is, the separation of a part 

 of the organ in the form of lifeless compounds, begins. 



The change of matter, the manifestation of mechani- 

 cal force, and the absorption of oxygen, are, in the 

 animal body, so closely connected with each, other, that 

 we may consider the amount of motion, and the quantity 

 of living tissue transformed, as proportional to the 

 quantity of oxygen inspired and consumed in a given 

 time by the animal. For a certain amount of motion, 

 for a certain proportion of vital force consumed as me- 

 chanical force, an equivalent of chemical force is mani- 

 fested ; that is, an equivalent of oxygen enters into 



