430 STUDIES IN ADVANCED PHYSIOLOGY. 



therefore, the total number of sympathetic ganglia twenty- 

 four pairs and one; that is, forty-nine ganglia. The gan- 

 glia on each side are connected with each other by means 

 of nerves, while the first ganglion in the cervical region is 

 connected in turn with the brain. 



In addition to the connections which each ganglion has 

 with the one preceding and the one following, two other 

 nerves arise from it. One of these is the communicating 

 branch already referred to in the description of the spinal 

 cord, a branch by means of which the sympathetic ganglion 

 is anatomically connected with the spinal cord. The other 

 is the visceral nerve proper, the nerve trunk distributed to 

 the viscera, carrying to the same the impulses of this cen- 

 tral ganglion, or conveying to these ganglia impulses from 

 the viscera. A very important nerve of this kind is the 

 sympathetic nerve which reaches the heart and is already 

 familiar as the cardio-accelerator. The visceral branches 

 of a number of abdominal ganglia unite to form a common 

 nerve trunk on each side called the splanchnic nerve. This 

 nerve is distributed to the abdominal viscera through the 

 solar plexus in the mesentery. 



The term sympathetic is a rather unfortunate one, as it 

 frequently leads to the impression that it is mainly concerned 

 with phenomena to which the somewhat vague term of sym- 

 pathy is applied. That, to use a stereotyped expression, it 

 keeps one part of the body in sympathy with another. 

 Such an expression is, of course, from a scientific standpoint 

 perfectly meaningless. If the term " visceral" system could 

 be generally applied to it this misinterpretation might be 

 avoided, while at the same time the term "visceral" would 

 give a clue to the function of this system which is in a 

 general way concerned with the physiological activities of 

 the visceral organs. 



General Histology. 



Having in the previous paragraphs called attention to 

 the systems as a whole and their relation to each other, the 



