162 FRANCIS M. POTTENGER 



single sensory or psychical impression which does not, at least theoretically, 

 affect the vegetative nerves and endocrin glands. Further, if the impres- 

 sions are strong, they upset the equilibrium in the endocrin and vegetative 

 systems and produce symptoms of disease. Many symptoms which mani- 

 fest themselves in the so-called vegetative structures (smooth musculature, 

 heart, and secreting glands) are due to disturbances in the normal physio- 

 logic equilibrium, of these two systems. 



Not only are both the endocrin and vegetative systems subject to 

 impulses of a physical nature, but each system is influenced by psychical 

 impulses and by impulses which originate in the other system. It is now 

 our purpose to inquire into this relationship and show, as far as we are 

 able, how the vegetative nerves influence the endocrin glands and how the 

 chemical substances produced by these glands influence the visceral nerves. 



Morphology of the Autonomic Nervous System. The autonomic or 

 vegetative nervous system, as illustrated in Plate I, consists of two divi- 

 sions, the sympathetic and parasympathetic. The sympathetic division of 

 the vegetative nervous system is sometimes called the thoracicolumbar out- 

 flow, because it takes its origin in the cord from the thoracic and upper 

 lumbar segments. The parasympathetic division, on the other hand, is 

 called the craniosacral outflow, because the nerves composing it arise from 

 the brain and the sacral portion of the spinal cord. Thus, the vegetative 

 fibers in the third nerve arise in the midbrain, those in the seventh, ninth, 

 and tenth in the bulb, and the pelvic nerve in the sacral segments of the 

 cord. The parasympathetic division is also sometimes called the "autono- 

 mic" or a vagus system" ; but the use of the term parasympathetic is prefer- 

 able, because autonomic is also applied to the entire vegetative system, 

 hence the use of it as applied to one division leads to confusion. Another 

 source of confusion, particularly in the earlier literature, is the use of the 

 term "sympathetic" as synonomous with "autonomic" as above defined. 

 Certain of the body structures are innervated wholly by one division of the 

 autonomic system and others by the other; again, structures are activated 

 by one division and inhibited by the other. 



There arc certain centers in the brain for the regulation of many impor- 

 tant functions presided over by the vegetative system. These centers may 

 be looked upon as being receiving and despatching stations, through which 

 integration of action is maintained. It is here that impulses are received 

 and transferred to the proper neurons to produce action in the terminal 

 effector mechanisms. There is a sympathetic center in the brain, which 

 K (linger suggested as lie ing in the midbrain, and Karplus and Kriedl have 

 described as lying near the tuber cinereum. It is significant that these 

 sympathetic centers lie in the same area as those which control such 

 functions as thermogenesis, polyuria, and vasomotor changes. 



Stimuli which act upon the sympathetic system may either act on the 

 sympathetic centers in the brain and cord, or on the true sympathetic 



