1905.] Distribution of Chlorides in Nerve Cells and Fibres. 187 



degree of fibrillation was found by Frommann and Grandly, but their results 

 in tbis respect may be explained as due to the same cause, for they left 

 a weak solution of the reagent in contact with the cells for a time sufficient 

 to bring about alterations in structure. 



Nerve cells are very difficult of penetration by the acid reagent, and in 

 consequence tbose of the sympathetic and spinal ganglia in vertebrates, and 

 of the ganglionic cord in Crustacea (lobster and crayfish), only rarely give a 

 reaction extending throughout all the cytoplasm, this being limited usually to 

 the more peripheral portions of the cell protoplasm. So deep, however, was 

 this peripheral reaction in certain cases, that the interior of the cell, including 

 the nucleus, was obscured. When the whole of the cytoplasm was uniformly 

 affected, the colour was less pronounced, and the nucleus with its silver white 

 appearance was visible. The deep reaction limited to the periphery in some 

 of the cells, and the lighter diffuse reaction in others, seem to suggest that 

 when the reagent does not readily penetrate, the chloride present diffuses out 

 to meet the silver salt and, accordingly, to give in the outer zone of the 

 cytoplasm a silver chloride deposit more abundant than that which would be 

 there if there were no diffusion and redistribution of the chloride. In the 

 pressed-out preparations of the cord of the guinea-pig and frog, the reagent 

 gained access at once to the cytoplasm of many of the cells because the 

 greater part of the surface of each was thus exposed to the solution, but 

 in not one instance did the reaction advance beyond the brownish-yellow 

 colour. 



The light reaction of the cytoplasm, considered with the fact that the 

 latter is usually voluminous, may be held to signify that the protoplasm 

 of nerve cells is less rich in the chloride than is the axon which arises 

 from it. 



In several preparations we found such a disposition of the chloride 

 reaction in the cytoplasm as to make us question whether the Nissl granules 

 contain any of the chloride present in the cytoplasm generally. The reagent 

 does not bring out these granules usually, and when they are seen, it is 

 through the cytoplasm coloured by the reaction. They thus appear affected 

 by the reaction, and it is consequently difficult to say whether they are free 

 from chlorides or not. 



That the nucleus of the nerve cell is free from chloride compounds is not 

 true only of these cells, for the senior author's observations go to show that 

 the nuclei of all cells, animal and vegetable, which are in a normal condition 

 are absolutely free from chlorides. 



