258 STUDIES IN ELECTRO-PHYSIOLOGY: 



sebaceous glands, and so forth, it will be found that 

 differences of resistance imply differences of level, and that 

 those differences, as shown hy the galvanometer, may, 

 with care, guide the way to correct diagnosis. 



Some physiologists have endeavoured to explain wide 

 deflectional differences as being due to varying conditions 

 of contact, that is to say, to the presence of more or less 

 moisture in the skin. But in pyrexia, local or otherwise, 

 moisture is conspicuous rather by its absence than its 

 presence, and it will be found that a hot, dry skin will, 

 when it is associated with inflammation, always give a 

 higher deflection than is obtainable from any part of the 

 body not so affected. 



In febrile diseases it is generally the first care of the 

 physician to get the skin to act. 



Moreover, experience has shown that in a number of 

 cases of nervous asthenia the hand-to-hand deflections, 

 despite the fact that the palms were wet, were all low 

 (40 or 50 mm.) and all negative, reverting only to the 

 positive side of the scale upon convalescence. 



IMPAIRED CONDUCTIVITY. 



A converse condition is when there is a partial failure 

 of inter-cellular conduction, due either to increased resist- 

 ance of the nerve-substance or to some change in the ionic 

 cell contents by which they are rendered less active. It 

 very frequently happens that a painful disorder is diagnosed 

 as neuritis or sciatica and that treatment gives no relief. 

 True neuritis, as I understand it, is an inflammatory 

 condition, caused by the insulation resistance of a sheath 

 of nerve or nerves being interfered with by local pyrexia. 

 In my experience the neuritis we hear so much about is 

 sometimes not so. It is, perhaps, in five cases out of ten, 

 due to some toxin. Pyorrhcea, the internal administration 

 of nux vomica, post-diphtheritic poisoning, inoculation by 



