274 DR. PHILIP'S OBSERVATJONS ON HT 



those whose power of volition is impaired by disease. He will find the patient 

 hesitate which leg to move at every step, and at length his attempts to move 

 the limbs produce a confused and irregular action incapable of carrying him 

 forward. 



The act of expanding the chest is an act of volition, it is an act in ordi- 

 nary breathing rendered extremely easy by the gentleness of the motion re- 

 quired, and the continual habit which renders it familiar, and is excited by a 

 sensation proportionably slight, but which is as essential to it as stronger sen- 

 sations are to more powerful acts of volition. Thus it is that on the removal 

 of the sensorial power respiration ceases. It may be here said perhaps, that we 

 have no instance of a muscle of voluntary motion continuing to act at short 

 intervals during life ; but besides that this is begging the question, it is to be 

 recollected that the action of the muscles in ordinary respiration is very slight, 

 and performed at considerable intervals, for it is only during inspiration that 

 the muscles act. They are quiescent during expiration, which in our usual 

 breathing is performed by the elasticity of the cartilages and the weight of the 

 parts concerned. There is perhaps no muscle of the body which could not 

 without fatigue maintain a similar action were there a cause capable of exciting 

 it. In certain diseases we find both more powerful and more frequent actions 

 of the muscles of volition continued for years during the whole of our waking 

 hours without any complaint of fatigue. 



Wlien the change in the blood, effected by respiration, no longer takes place, 

 most of the pulmonary vessels lose their proper stimulus, red blood ; and feel 

 more directly perhaps the debilitating influence of black blood ; their functions 

 therefore begin to fail. In proportion as this happens, the blood accumulates 

 in the lungs. The right side of the heart consequently experiences an increased 

 difficulty in emptying itself, and the due supply of blood to the left side fails. 

 By the operation of these causes both sides of the heart, particularly in warm- 

 blooded animals, soon lose their power after respiration ceases. The arteries 

 under such circumstances, it is evident, cannot long supply fluids proper for 

 the purposes of assimilation. The nervous and muscular solids therefore deviate 

 from the state necessary for the functions of life, which at length cease in eveiy 

 part. 



The foregoing appears to be the order in which the functions always, with 



