The Chemistry of Nerve-degeneration. 



149 



streams of positive ions would give a direction opposite to that 

 observed, and if the rotation were produced by the changing strength 

 of the magnetic field upon the negative ions, then also would the 

 direction of rotation be opposite to that actually obtained. The 

 viscosity of the gas would tend to annul any sudden twist which the 

 changing magnetic field might give to the cloud of negative ions 

 within the bulb, although the reaction set up between the magnets 

 and the ions under such conditions would be sufficient to cause the 

 negative particles to be thrown forward, and to concentrate in a 

 manner consistent with the experimental results given. It is not clear, 

 however, why the sudden cessation of the magnetic field should also 

 produce such a concentration of negative ions. But we have already 

 seen that under those conditions diselectrification is easily produced ; 

 moreover, a luminous ring that has grown dim, can usually be momen- 

 tarily brightened by suddenly destroying the magnetic field. 



A pause was sometimes noticed between the excitation of the 

 magnets and either the formation of the ring or the loss of charge 

 from a positively electrified body. 



This result showed that the steady magnetic field itself so modified 

 the paths of moving negative ions within the bulb, that a concentra- 

 tion of them at the strongest part of the field took place for this reason 

 also. 



The direction of rotation of the luminous ring can be accounted for 

 in the following manner : — - 



When the potential difference between the accumulation of negative 

 ions at the centre of the bulb and the layer of electrified gas upon the 

 inner surface of the glass is such that a shower of incoming positive 

 ions occurs and the luminous ring appears, the outer portion of the ring 

 will be more positive than the surrounding negatively electrified cloud 

 of gaseous particles. These will therefore be attracted inwards, and in 

 that way give a rotatory motion to the luminous gas-mass in the 

 direction actually observed. 



" The Chemistry of Xerve-degeneration." By F. W. Mott, M.D., 

 F.B.S., and W. D. Halliburton, M.R, F.K.S. Keceived 

 March 1 — Bead March 14, 1901. 



(Abstract.) 



We have previously shown that in the disease, General Paralysis of 

 the Insane, the marked degeneration that occurs in the brain is accom- 

 panied by the passing of the products of degeneration into the cerebro- 

 spinal fluid. Of these, nucleo-proteid and choline are those which can 

 be most readily detected. Choline can also be found in the blood. 



