EXTRACT XXXIV. c. 



ON THE PRINCIPLE OF RECIPROCITY BETWEEN THE 

 SYMPATHETIC AND SYSTEMIC NERVOUS SYSTEMS. 



WE have already endeavoured to make clear that the 

 nervous system of man is dual, in anatomical structure, 

 in functional control of the working of the physiological 

 life of his organs and textures, and in the determination 

 of the destiny of his component parts, physical and meta- 

 physical, material and immaterial. 



These nervous systems are evolved in succession, the 

 sympathetic first and the systemic second, from the uni- 

 cellular organism called the fecundated ovum, the first, or 

 sympathetic, being, in turn, instrumental in evolving the 

 second, or systemic. They each, we have seen, while 

 retaining their respective nervine individualities, act and 

 react on each other, and perform their individual functions 

 in the economy of the body generally, while they unite in 

 the performance of the " thousand and one " common 

 functions, in the bonds of a common origin, and to meet 

 the necessities of a common organism, for common pur- 

 poses, to the end that one great common organic object 

 may be attained. 



This principle of dual control, within the physiological 

 working of the human organism, necessitates the existence 

 of a " treaty of reciprocity," so to speak, between the two 

 systems, determines the limits of individual freedom of 

 working and administration within the limits of the 

 common organism, and prescribes the occasions on which 

 joint action is necessary to accomplish common ends. 

 The importance of such a provision in the dual working 



