AND ANIMAL LIFE. 303 



of the heart remains when the brain and spinal 

 cord are destroyed. If this be acknowledged, the 

 opinion, that the transmission of the nervous power 

 into the muscular fibres of the heart is necessary 

 to excite or sustain its motion, cannot be receiv- 

 ed in the present state of physiology ; and there- 

 fore the explanations which he gives of the great- 

 er part of the phenomena of Syncope, are theore- 

 tical speculations. 



CCCXXXIII. In the present chapter, the re- 

 mote causes of Syncope are divided into two 

 general classes. The first contains those causes 

 which act upon the external senses and the mind : 

 The second, those 'which act upon the functions of 

 respiration and circulation. 



The first class is again subdivided into affec- 

 tions of the senses, such as past impressions, and 

 the pleasurable or painful states of the body. 



The second class may be subdivided into those 

 causes which act directly or indirectly upon the 

 heart and the respiratory function. 



CCCXXXIV. In investigating the action of 

 the individual causes included under each subdi- 

 vision, we shall find that everyone of these tends to 

 produce the same proximate cause an overcharged 

 state of the heart. This condition of the heart 

 should not be regarded as an effect of its own de- 

 bility, as generally believed, but is to be referred 

 to the greater demand made upon its powers by 



