80 



G B X ERAL CONCLUSIONS. 



This table shows, that, as a general rule, the activity of the respiratory function 

 corresponds with the rapidity of the circulation. 



We are now prepared to understand the results of our experiments, and to show 

 that the operations of nature are carried on upon the same great plan, however 

 simple or complex the animal. 



Cold-blooded animals are such, not from any peculiar chemical or physical endow- 

 ments of the organic and inorganic molecules of their bodies, but from the pecu- 

 liarity of the structure of their circulatory and respiratory systems. 



The perfection of these two systems may be taken as the index of the rapidity 

 of the physical and chemical changes of the molecules of their fluids and solids, and 

 the facts we have presented lead to the conclusion, that the intelligence and acti- 

 vity of the vital actions are exactly proportional to the rapidity and amount of the 

 physical and chemical changes of the organic and inorganic molecules. 



Our investigations show that the heart of warm-blooded animals is from two to 

 five times as heavy as that of reptiles, and is far more rapid and powerful in its 

 actions, and, as a necessary consequence, that the blood circulates with much 

 greater rapidity. 



The respiratory system of reptiles is imperfectly developed, and its functions 

 imperfectly performed. Only from one-sixth to one-ninth as much blood passes 

 through their lungs, and is exposed to the action of the atmosphere, as circulates 

 through the pulmonary organs of warm-blooded animals. 



The blood-corpuscles, the active agents in the elaboration of many of the consti- 

 tuents of the blood, are much less numerous, and the whole amount of blood exist- 

 ing in their bodies is much less abundant in cold than in warm-blooded animals. 



The nervous system, the great apparatus for the generation of the excitor-motive 

 power of the animal economy, is imperfectly developed in cold-blooded animals. 



From these data we are able to calculate, with almost absolute certainty, that 

 the vital actions of cold-blooded animals should be from one-ninth to one-fifteenth as 

 rapid as those of warm-blooded animals. Here we have a conclusive demonstration 

 that modifications in vital phenomena are accomplished by peculiar modifications 

 of the structure and arrangements of the various organs and apparatus, and by 

 peculiar applications of the forces, and not by a suspension or alteration of the 

 physical and chemical laws which govern all matter. 



