244 ANDREW JACKSON HOWE. 



The movement is not chemical nor mechanical, but it 

 arises from vital peculiarities not well understood. 

 Vitality is an attribute of organic matter, and too 

 complex and subtle to be analyzed by the chemist. 

 It is not satisfactory to say that the more limpid and 

 oxygenated arterial blood chases denser venous blood 

 through the capillaries into the veins, as the thin sap 

 pushes along the thicker. 



The heart throws the blood through the arteries 

 to the capillaries, and there the cardiac impulse is lost. 

 A new agency is now needed to take the blood 

 through the capillaries into the venous radicles. 

 Possibly the capillary walls possess a force which has 

 never been demonstrated. Probably it is of a com- 

 pound nature, like most vital operations. Many in- 

 genious experiments have been performed, and plaus- 

 ible theories invented to explain the movement of the 

 blood in the capillaries, yet here is still room for an 

 important discovery. It is a promising field in which 

 to prospect for scientific nuggets. 



Nervous ganglia or isolated centers of nerve force, 

 in the walls of the heart will maintain a throbbing 

 motion even when no blood is present, and the pulsat- 

 ing organ is removed from the body. Even the hearts 

 of birds after they have been removed, if preserved 

 warm and moist, may be kept throbbing for many 

 minutes. This force is essential to the vital continu- 

 ance of inferior animals. It tides some creatures over 

 the winter sleep, saving them from asphyxia and 

 death. These separate and independent centers ot 

 nervous energy may move the capillary walls or the 

 fluids within them. These ganglia are, as it were, the 

 cells of a vital battery, which at length will cease to 

 act after their source of supplies for generating ac- 



