ON NERVINE SECRETION 



79 



The general cutaneous surface (Figs. 16, 17, 18) may 

 be said to afford the largest area for the requirements of 

 the economy of systemic nervine excretion. It will be 

 observed, however, in this enumeration of eliminatory 

 means, that apparently no provision is thereby provided 

 for the excretory necessities of the sympathetic nervous 

 system. This, however, we think can only be apparent, 

 not real, because its trophic functions demand the fullest 

 excretional facilities which can be afforded, and on the free 



FIG. 13. SECTION OF THE UPPER PART OF THE BRAIN AND MENINGES 



TO SHOW THE RELATIONS OF THE ARACHNOIDAI, VILLI. (Key and 



Retzius.) Magnified. 



c, c, corpus callosum ; f, falx cerebri ; s.a, subarachnoid space, pervaded by a net- 

 work of fine trabeculae; from it the fungiform villi are seen projecting into the 

 dura mater. Some are projecting into the superior longitudinal sinus, J. 



surfaces of the skin, and of the mucous and serous mem- 

 branes lining the various cavities of the body, as well as 

 on the various synovial surfaces of the joints and bursae, 

 and through the great excretory organs, the kidneys. It 

 will thus be seen that the sensory side of the nervous 

 system proper, and the sympathetic system, are provided 

 with an abundant and ready means of relieving themselves 

 of their waste products, but that the motor side of the 

 nervous system proper is not correspondingly provided 

 for. When, however, we consider the matter in its 

 details we think we will be able to see that excretion even 

 here is effected by and through the terminal nerve fibrils, 



