14 THE NERVOUS SYSTEM AXU ITS COXSKKYATK )\ 



\Yhat \V(uld remain for the fourth member of thi- 

 uncanny series? It has been reserved for a reconstruc- 

 tion of the nervous tissues. A distant view of it would 

 give the impression of a ghostly form with a more sub- 

 stantial axis expanding above into a bullions mass in the 

 head. On closer approach the axis would prove to be the 

 spinal cord, the enlargement above would be recogni/ed 

 as the brain, and the filmy haze which completed the 

 figure would resolve itself into many nerves, branching 

 strands proceeding from both brain and cord and termin- 

 ating in a cloud of finest filaments. These filament - 

 would be found to reach almost every part of the body 

 (Fig. 1). A large proportion would be seen to end near 

 the external surface; a great many could be followed to 

 localities previously determined to correspond with t he- 

 skeletal muscles; still others would be manifestly adapted 

 to make connections with blood-vessels, glands, and the 

 contractile elements of the viscera. 



By way of recapitulation the following statements may 

 now be made: The human body or the body of any 

 animal of a highly organized type owes its relative 

 constancy of form to an inactive supporting system, the 

 connective tissues. It owes its ability to move to the 

 contractile tissues. The epithelial tissues are those which 

 establish the boundaries between the organism and the 

 environment; through them exchanges of gaseous and 

 ili-M.lve.d substances take place. The service of the 

 nervous tissues remains to be indicated. The task is to 

 occupy u- throughout the present volume. But a con- 

 densed preliminary discussion is desirable. 



It' .-, u-ord is sought which shall convex a general idea 

 of the work of the nervous system, it is probable that 

 the term foortliiKitinn will suggest itself.. The nerves 

 serve to place various parts of the body in communica- 

 tion. This statement must be followed at once with the 

 note that the communication afforded i- newer <l/'i-<'<-llt/ 

 from on/an In m-i/un, but always by way of the axial part 

 of the system. Thus, there is no unbroken nervous high- 



