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The Chemistry of Nerve-degeneration. 



We have continued our work, and we find that this is not peculiar to 

 the disease just mentioned, but that in various other degenerative 

 nervous diseases (combined sclerosis, disseminated sclerosis, alcoholic 

 neuritis, beri-beri) choline can also be detected in the blood. The 

 tests we have employed to detect choline are mainly two : (1) a 

 chemical test, namely, the obtaining of the characteristic octahedral 

 crystals of the platinum double salt from the alcoholic extract of the 

 blood; (2) a physiological test, namely, the lowering of blood pressure 

 (partly cardiac in origin, and partly due to dilatation of peripheral 

 vessels) which a saline solution of the residue of the alcoholic extract 

 produces ; this fall is abolished, or even replaced by a rise of arterial 

 pressure, if the animal has been atropinised. It is possible that such 

 tests may be of diagnostic value in the distinction between organic and 

 so-called functional diseases of the nervous system. The chemical test 

 can frequently be obtained with 10 c.c. of blood. 



A similar condition was produced artificially in cats by a division of 

 both sciatic nerves, and is most marked in those animals in which the 

 degenerative process is at its height, as tested histologically by the 

 Marchi reaction. A chemical analysis of the nerves themselves was 

 also made. A series of eighteen cats was taken, both sciatic nerves 

 divided, and the animals subsequently killed at intervals varying from 

 1 to 106 days. The nerves remain practically normal as long as they 

 remain irritable, that is, up to three days after the operation. They 

 then show a progressive increase in the percentage of water, and a 

 progressive decrease in the percentage of phosphorus, until degenera- 

 tion is complete. When regeneration occurs, the nerves return approxi- 

 mately to their previous chemical condition. The chemical explanation 

 of the Marchi reaction appears to be the replacement of phosphorised 

 by non-phosphorised fat. When the Marchi reaction disappears in the 

 later stages of degeneration, the non-phosphorised fat has been absorbed. 

 This absorption occurs earlier in the peripheral nerves than in the 

 central nervous system. 



This confirms previous observations by one of us (M.) in the spinal 

 cord in which unilateral degeneration of the pyramidal tract by brain 

 lesions produced an increase of water and a diminution of phosphorus 

 in the degenerated side of the cord, which stained by the Marchi 

 reaction. 



The full paper is illustrated by tracings of the effects on arterial 

 pressure of the choline separated out from the blood of the cases 

 of nervous disease mentioned, and from the blood of the cats 

 operated on. 



Tables are also given of the analyses of the nerves, and drawings 

 and photo-micrographs from histological specimens of the nerves. 



A summary giving the main results of the experiments on animals 

 is shown in the following table : — 



