94 THE ACTIVE FORCES OF LIVING ORGANISMS 



the degree of tension being raised, will be thrown into 

 a state of abnormal vibration under an expanding 

 influence ; and when at the termination of the bath 

 this influence is, as always happens, suddenly re- 

 moved, it is only natural that a change in the nervous 

 rhythm should take place, and that it should be in 

 the direction of contraction. On the other hand, if 

 the bath be below blood-heat, the change of rhythm 

 or reaction would be towards expansion. Owing to 

 the fact that the nervous system is raised during the 

 passage of the electric current to a higher state of 

 tension, the effects produced are likely to be in most 

 instances of a comparatively more permanent nature 

 than is the case when a simple bath is taken. The 

 effect of an electric bath may also be said to depend to 

 some extent on the state of the blood-pressure in the 

 nerve-centres as determined by the position of the 

 body, especially if the electrodes be applied to the 

 spine or head. Variations of blood-pressure affect a 

 delicate nervous system even without the application 

 of electricity. Many persons sleep better on a high 

 pillow ; many, also, do not enjoy perfect repose when 

 lying on the back. An increase of blood-pressure in 

 the nerve-centres causes an increase of expansion and 

 greater activity, hence the tendency to wake or dream 

 when one is lying on one's back. Under the influence 

 of the electric current these effects are increased, and 

 accordingly the reaction or change in the nervous 

 rhythm, which takes place when the current is cut 

 off, is correspondingly greater. Similar, though still 



