156 Journal of Comparative Neurology and Psychology. 



sis of the fluid do not concern us here. The chemistry of the fluid 

 will be touched upon, only so far as it relates to the products of mye- 

 lin decay. The physical chemistry of the fluid (freezing point, etc.), 

 the various proteids and the reducing body are all of interest, but their 

 consideration would exceed the scope of this review. 



The most important chemical substance which passes into the cer- 

 ebrospinal fluid is cholin, which is the nitrogen-containing methyl 

 group of lecithin, and can be looked upon as one of its autolytic de- 

 composition products. In the normal fluid it is found in mere traces, 

 but in the fluid fiom cases of general paralysis, as hrst shown by Mott 

 and Halliburton, large amounts are present. Since Halliburton 

 first demonstrated cholin in general paralysis, in his Croonian lectures 

 on the chemical side of nervous activity, it has been found in a multi- ■ 

 tude of other pathological conditions, but principally where recent 

 and active nerve degeneration is taking place. The ilecithin of the 

 myelin sheaths of nerves, is decomposed, probably through the agency 

 of some enzyme, into glycerophosphoric acid, stearic acid, and cholin. 

 This latter is found in the blood and cerebro-spinal fluid, while it is ab- 

 sent from the urine, except in experiments on animals, where the alka- 

 loid is given subcutaneously or intracerebrally. When cholin appears 

 in the fluid, there is also an increase of phosphoric acid therein (DoN- 

 ath), this being another proof of its derivation from lecithin. In 

 long continued activity of the central nervous system, as in convulsive 

 seizures, lactic acid in large quantities appears in the cerebro-spinal 

 fluid. 



Cholin is detected by means of its platinum combination, with which 

 it forms a double salt, and crystallizes in single large yellow octahedral 

 and occasionally twin crystals, and easily differentiated from the plati- 

 num salts of neurin and potassium, by reason of its solubility, percent- 

 age of platinum and large size and grouping of the crystals. Since 

 Halliburton first pointed out its occurrence in general paralysis, the 

 work has been further elaborated by Mott, Wilson, Donath and 

 CoRiAT. As a result it is found in many pathological states, where 

 there is an axonal reaction with corresponding fiber degeneration (cen- 

 tral neuritis), general paralysis, brain tumor, tabes, Huntington's 

 chorea, delirium tremens, polyneuritis, epilepsy, senile dementia (es- 

 pecially where there is great wasting of the cortex), cerebral hemor- 

 rhage, beri-beri, Pott's disease, disseminated sclerosis, amyotrophic lat- 

 eral sclerosis, focal myelitis, organic dementia, brain syphilis, chronic 

 hydrocephalus (?) spina-bifida, neurasthenia ( ? ) and hystero-epilepsy. 

 It has also been found in the blood of animals after experimental sec- 



