FUNCTIONS OP THE STOMACH. 309 



less marked degree, and vomiting is a prominent symptom of 

 acute intoxications. The sudden appearance of a great amount 

 of suprarenal secretion and a corresponding increase of oxidiz- 

 ing substance in the blood would obviously cause not only 

 vomiting, but general gastric activity, were its penetration to 

 the walls of the stomach and the secretory structures not gov- 

 erned in some way. Whether there are both efferent and 

 afferent vagus fibers in the cceliac plexus it is at present im- 

 possible to tell; but, even if afferent filaments did not exist, 

 the enhanced activity of the vagus center incident upon the 

 increased local metabolism would act as an efficient controlling 

 factor, since it would assist the motor system similarly over- 

 excited in causing enhanced constriction of all the blood- 

 channels. The wealth of nervous structures over the coeliac 

 axis suggests that this protective effect is primarily exerted 

 in this location, thus preserving more or less according to 

 the power of the toxic the integrity of the stomach, liver, 

 pancreas, spleen, and other structures supplied through the 

 cceliac trunk. 



When all these facts are considered and the kinship of 

 the functions involved with those of organs previously studied 

 is fully appreciated, the following deductions seem war- 

 ranted: 



1. The nerves of the stomach are derived from two auton- 

 omous sources: the general motor system (sympathetic) and the 

 vagus system. 



(a) The general motor system supplies efferent nerves, which 

 serve to maintain tonic contraction of the arteries and to insure 

 the functional efficiency of all gastric structures during the passive, 

 or resting, period. 



fb) The vagus system supplies loth sensory and motor nerves, 

 ivhich excite and govern the functions of the stomach during its 

 active period: i.e., digestion. 



2. The extrinsic efferent nerves of the stomach, also derived 

 from the general motor and vagus systems, accompany the organ's 

 arterial supply and jointly constitute its extrinsic vasoconstrictor 

 system: i.e., that through which the Hood-flow in the organ is in- 

 creased. 



3. The intrinsic efferent nerves are divided into two sets: (1) 



