AND ANIMAL LIFE. 279 



1. That the heart is influenced by mechanical agents of 

 every description applied to the brain, in proportion to 

 the disturbance induced in the sanguiferous system. 



%, That the heart is influenced by chemical agents applied 

 to the brain, according to the extent of surface, or ce- 

 rebral substance occupied by the individual agent, as 

 the absorption of the same is regulated by these con- 

 ditions. 



3. That the heart is affected in degree according to the 



strength and quantity of chemical means employed, 

 and the vicinity of their application to it. 



4. That the heart can be influenced by galvanism equally 



well through nerves, veins, and arteries, through 

 the substance of the brain, mucous membrane of the 

 nose, food in the stomach, and moistened thread ; 

 indeed the effect produced appears independent of 

 any organic inherent quality. 



5. Those parts of the animal frame appear the most 



powerfully excited by galvanism which seem to be 

 endowed with the greatest quantity of motory nerves, 

 viz. the extremities, the heart, diaphragm, and mus- 

 cles of the face. 



6. That the heart is not protected from irregularity be- 



cause it derives its power from the whole brain, but 

 because it has no nervous or direct connexion with the 

 cerebral mass of the hemispheres through which it can 

 be readily affected. 



7. It would also appear probable, that the irritability or 



motory property of the heart was not materially 

 affected by the destruction of the brain and spinal 

 cord, as its contractions were found to continue long 

 after their removal, if the circulation of the blood were 

 maintained by inflation. This circumstance is ex- 

 tremely favourable to the opinion expressed in the pre- 

 ceding inference. 



