SYMPATHETIC NERVOUS SYSTEM. 417 



the idea that there is little else in the literature of the sub- 

 ject than controversial questions of priority, etc., in minor 

 details, and a few observations, some of them quite unsatis- 

 factory, with regard to the effects of the division or galvani- 

 zation of sympathetic filaments upon the functions of circu- 

 lation, secretion, and animal heat. "We can hardly venture 

 to hope that this chapter will be exceptional in this regard, 

 unless we pass over very briefly the bibliographical discus- 

 sions so elaborately presented by many authors. It is un- 

 fortunate that well-ascertained facts, which might be stated 

 in a very few pages, should be so largely overshadowed by a 

 mass of purely historical details of no great interest. Still, 

 we must take the physiological data as we find them, and 

 endeavor not to limit the knowledge to be looked for in 

 the future, by adopting theories upon insufficient positive 

 evidence. 



There are certain important anatomico-physiological ques- 

 tions, more or less definitely determined, that have a direct 

 bearing upon the functions of the sympathetic system. These 

 are the following : Is the sympathetic anatomically and physi- 

 ologically dependent upon its connections with the cerebro- 

 spinal nerves ? What are the general properties of the sym- 

 pathetic nerves as regards motion and sensation ? Do the 

 sympathetic ganglia act as independent reflex nerve-centres ? 

 To what extent and in what way do the sympathetic gan- 

 glia and nerves influence the functions of the various organs 

 and tissues to which their filaments are distributed ? A so- 

 lution of these questions involves a careful and critical study 

 of the results of experiments on living animals and of patho- 

 logical facts ; and it is evident that very little information 

 is to be derived from observations made anterior to the dis- 

 covery of the properties and functions of the most important 

 parts of the cerebro-spinal system. We will begin the study 

 of these points with an account of the general arrangement 

 and the peculiarities of structure of the sympathetic ganglia 

 and nerves. 



