Herrick, Physiology of the Nervous Elements. 139 



of nerve force which keeps blood-vessels and muscles in a 

 state of tonic contraction which is delicately adjusted to 

 every fluctuating external and internal condition. The 

 nervous system is an automatic governor regulating the 

 blood pressure, secretions and nutrition of the entire 

 body. 



It is only now being recognized that cvoy centrifugal 

 nerve is concerned in the nutrition of the organs to which 

 it passes. Section of a nerve causes the atrophy or de- 

 generation of the tissues supplied by it. The wonderful 

 effect which nervous processes may have on the growth, 

 dev^elopment or decay of the body are not yet appreciated. 

 It is entirely scientific to suggest that a state of mind could 

 produce a poison within the system capable of engendering 

 severe disease, or, on the contrary, a secretion capable of 

 affording immunity against contagious disease. In fact 

 recent studies in the treatment of cholera and other germ 

 diseases are bringing to light unsuspectedly close relations 

 between the nervous processes and immunity. It has 

 been discovered that epilepsy (apparently a purely nerv- 

 ous affection ) may be produced by innoculation and may 

 be fortified against, if not even cured, by the innoculation 

 of suitably prepared lymph. It is another remarkable fact 

 that, in such susceptible animals as the guinea pig, section 

 of the principal (sciatic) nerve of the leg will produce 

 modifications of the tissue of the neck forming epileptogene 

 zones which upon irritation give rise to all the symptoms 

 of epilepsy. While this process is not understood, it 

 might be suggested that the nutritive disorders resulting 

 from the section of a large nerve may produce morbid sub- 

 stances in the lymph which would react on the proliferat- 

 ing (lymphatic) centres giving rise to a pathogenetic 

 lymph w^hich would affect the nerve centres. 



Such a speculation as this is indulged in simply to 

 show how closely the nervous and vital processes are as- 



