OF VITAL DYNAMICS. 673 



is disengaged in the lungs, where it converts chyle 

 and lymph into the proximate constituents of 

 blood, and raises its temperature, by which the 

 heart is excited to contract, and send the vital 

 stream to all parts of the animal system. And 

 as the power of steam to move the piston is des- 

 troyed on parting with its caloric in the con- 

 denser, so is that of arterial blood to maintain the 

 action of the heart, stomach, brain, and voluntary 

 muscles, diminished or destroyed by parting with 

 the caloric it receives in the lungs, while passing 

 through the ultimate tissues of the body, which 

 cannot be nourished and vitalized by dark venous 

 blood, for the simple reason, that its tempera- 

 ture has been reduced to an equilibrium with that 

 of the solids, and its vital properties impaired, 

 until again renovated by respiration. 



Thus it is manifest, that when stripped of all 

 hypotheses, arid reduced to its utmost simplifi- 

 cation, the science of animal physiology may be 

 reduced to a very small compass, that a differ- 

 ence between the temperature of arterial blood 

 and that of the solids is absolutely essential to all 

 the phenomena of life, that the transformation 

 of blood into the different organs depends on the 

 same attraction of fluids for solids that determines 

 the growth of vegetation, and the capillary circu- 

 lation in animals that have no heart, like that of 

 the lacteal and lymphatic absorbents. But why 

 should I waste time in maintaining a doctrine 



