AND ANIMAL LIFE. 263 



following considerations and experiments. The 

 sensorium, from its magnitude and the activity of 

 its functions, must necessarily receive a great 

 quantity of blood ; and whatever tends abruptly to 

 disorder its free transmission from the brain and 

 its reception to this organ, will manifestly influence 

 the contractions of the heart. 



CCLXXXV. When the brain is destroyed by 

 degrees, the heart is scarcely sensible of the 

 gradual loss of blood, or of the effects it in- 

 duces in the general sanguiferous system ; but 

 when the brain is instantaneously crushed, we 

 have other consequences. This operation gives 

 rise to three results, which go far to explain the 

 momentary cessation in the contractions of the 

 heart. 



First, The blood which is propelled along the 

 arteries in its passage to the brain is suddenly 



forced back upon the heart, or is stopped in its 

 course, and thereby prevents the circulation of the 

 next portion transmitted by the contractions of the 

 heart. 



Second, The circulation of blood in the veins is 

 equally disturbed. When the nervous mass is sud- 

 denly compressed, the blood that was previously 



jiowing regularly to the heart is sent either with 

 inordinate force, as it is in this direction alone it 

 can escape, or its circulation is completely stopped ; 

 it is probable that both conditions with modifications 

 occur. 



