THE FINER STRUCTUHE OF THE NEURONES IN THE 

 NERVOUS SYSTEM OF THE WHITE RAT 



Shinkishi Hatai 



The two problems which we have to consider are the fundamental structure of 

 the ground-substance of the nerve-cells and the manner in which the axone of one 

 neurone terminates on the dendrites or on the cell-body of another. Many opinions 

 and theories concerning this structure and these relations have been put forth during 

 the last decade, and as a consequence the literature of this subject is already very 

 large. Nevertheless it cannot be said that either of the questions has been definitively 

 solved. With the aid of a new technique we have been able to see some structures 

 and relations not heretofore described, and it is the object of the present paper to 

 interpret and depict these new appearances. 



I. TECHNIQUE 



For the present investigation a large number of white rats having body-weights 

 ranging from 5.4 to 185 grams were employed. The material was preserved with 

 Gilson's fluid, Carney's mixture, and the mixtures devised by the present writer 

 (1901) ; as the staining agents, saturated aqueous solution of thionin followed by a 

 1 per cent aqueous solution of erythrosin ; Heidenhain's iron-hsematoxylin, and 

 Ehrlich's triacid method were used. In applying these several methods the author's 

 directions were strictly followed. In each case, after imbedding in paraffin according 

 to the usual procedure, sections were cut three micra in thickness. 



Besides these methods, the present writer tried another method which gave very 

 satisfactory results in the study of the ground substance of the nerve-cells as well as 

 in that of the finer structure of their processes. This method is as follows : As soon 

 as the fresh material was removed from the body, it was put directly into the following 

 solution. The pieces should not be more than 5 mm. ^. 



1. Acetic-picric-formalin mixture (after the writer, 1901) - - 250 c.c. 



2. Acid fuchsin, saturated aqueous solution 50 c.c. 



After twenty-four hours the pieces were taken from the solution and were teased 

 in glycerin with fine needles. In this teased preparation only the achromatic substance 

 of the nerve-cells and processes stain, while the rest of the cell-substance remains 

 unstained. For this reason it offers us several advantages for the study of the minute 

 structure of the axone and dendrites not possessed by other methods which were 

 employed. Although this preparation gives such satisfactory results, it cannot be 

 preserved permanently, as the color soon fades. To meet this difficulty, the material 

 thus preserved and stained may be imbedded in paraffin after having been carried 



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