CIRCULATION AFTEK DEATH. 351 



either from lack of complete distention, or from imperfect 

 emptying of the cavities. 1 



Phenomena in the Circulatory System after Death. We 

 do not believe that any one has proven the existence of a 

 force in the capillaries or the tissues (capillary power) which 

 materially assists the circulation during life, or produces any 

 movement immediately after death; and shall not discuss 

 further the extraordinary post-mortem phenomena of circu- 

 lation, particularly those which have been observed by Dr. 

 Dowler in subjects dead of yellow fever. 1 But nearly every 

 autopsy shows that after death the blood does not remain 

 equally distributed in the arteries, capillaries, and veins. 

 Influenced by gravitation, it accumulates in and discolors the 

 most dependent parts of the body. The arteries are always 

 found empty, and all the blood in the body accumulates in 

 the venous system and capillaries ; a fact which was observed 

 by the ancients, and gave rise to the belief that the arteries, 

 as their name implies, were air-bearing tubes. 



This phenomenon has long engaged the attention of phys- 

 iologists, who have attempted to explain it by various 

 theories. Without discussing the views on this subject an- 

 terior to our knowledge of the great contractile power of the 

 arteries as compared with other vessels, we may cite the ex- 

 periment of Magendie, already referred to, 2 as offering a 

 satisfactory explanation. If the artery and vein of a limb be 

 exposed in a living animal, and all the other vessels be tied, 

 compression of the artery does not immediately arrest the 

 current in the vein, but the blood will continue to flow until 

 the artery is entirely emptied. The artery, when relieved 



1 These great variations in the value of the ventricular systole, amounting 

 even, in the experiment on the healthy animal, to a diminution of one-half, as the 

 result of exercise, show the uncertainty of the basis of those estimates with regard 

 to the time required for the entire mass of blood to pass through the heart, which 

 are calculated from the entire quantity of blood, the quantity discharged from the 

 heart at each pulsation, and the number of pulsations per minute. 



2 See page 295. 



