Is Choline present in the Cerebro-Spinal Fluid of Epileptics ? 295 



Donath's test, and a negative periodide reaction), ignited them in a 

 platinum dish, and extracted the residue with dilute hydrochloric acid. 

 Donath's test was again performed with this extract. Although all the 

 organic matter had been destroyed, nevertheless doubly-refracting crystals, 

 although less numerous than before, were obtained. It is clear, therefore, 

 that part at least of the anisotropic crystals represent inorganic substances. 



Table III. 



* In this case the fluid was removed twelve hours after death. 



This result led me to carry out a control experiment, using distilled 

 water instead of cerebro-spinal fluid. The method was carried through in 

 the usual way, and the inorganic salts employed (potavssium carbonate, 

 potassium chloride, and platinum chloride) were carefully purified specimens. 

 Finall3% under the polarising microscope a crop of doubly - refracting 

 crystals^ indistinguishable in quantity and form from those obtained in 

 cases of epilepsy, were obtained. I have repeated this several times with 

 the same result. This is illustrated by the accompan3nng photographs. 

 Fig. 1 shows the appearance of the doubly-refracting crystals obtained in a 

 blank experiment, using 20 c.c. of distilled water instead of cerebro-spinal 

 fluid. Fig. 2 shows the same from a case of genuine epilep.sy. If these are 

 compared with thase published by Donath,' they will be seen to be 

 practically identical. 



It is clear, therefore, that such crysttils are no proof of the presence of 

 choline, but owe their origin (at least in part) to minute impurities in the 



' Loc. cit., p. 215. 



