AND ANIMAL LIFE. 313 



CCCLIV. I have previously endeavoured to 

 show that the heart is not directly affected by 

 the mind through the intervention of nerves, but 

 by its action upon the function of respiration. The 

 muscles of respiration are partly subject to the in- 

 fluence of the will, and partly free from its opera- 

 tion. The involuntary influence is that power 

 which is particularly called into action by our sen- 

 sations, whatever be their origin or character. If of 

 an inspiratory nature, the ordinary motion of the 

 chest is disordered, and the consequence of this 

 change is, that a quantity of blood greater than 

 what is natural is determined to the thoracic or- 

 gans, creating palpitation from the increased de- 

 mand made upon the heart, or complete cessation, 

 from the great oppression. 



CCCLV. When fear makes a powerful im- 

 pression upon the mind, the individual draws a 

 deep sigh, or seems to give a continued inspira- 

 tion ; faintness is probably felt ; and the mode of 

 inspiring being but slightly interrupted by the 

 occasional or imperfect expirations, the lungs and 

 heart receive more blood than they are capable 

 of transmitting with accustomed regularity. It 

 is the relation of quantity to the capacity and ener- 

 gy of the heart that explains in part the definition 

 of CULLEN, " Motus cordis imminutus vel ali- 

 quandiu quiescens." As the susceptibility, sen- 

 sations, ancl organic adaptations are not alike in 



