The finer Structure of the Nerve Cells of Invertebrates. \Q 



In properly differentiated sections, the granules in the cell 

 body are stained a reddish hue, while the substance of 

 the cell between the granules, as well as the axis- 

 cylinder processes and neuroglia tissue, are stained 

 green. 



The safranin-light green combination was with slight modifications 

 used in a manner similar to that recommended by Benda. The 

 sections were stained in safranin (after Babes) for 24 hours, 

 then rapidly washed in distilled water which contained a few drops 

 of acetic acid, and finally differentiated in a solution of light green 

 (1 g in 100 ccm of 96 7o alcohol). The length of time which the 

 sections should remain in the light green is usually very short 

 (Vs — V2 niin.), but can only be accurately determined by washing out 

 the sections in 96 "/(, alcohol, and observing under the microscope 

 how far the substitution process has been carried. 



A combination of fuchsin and light green produces about the 

 same results as the last mentioned combination , but was not so 

 generally used as the latter, on account of the greater difficulty ex- 

 perienced in controlling the substitution process. The ordinary al- 

 coholic solution of fuchsin was employed in which the sections were 

 stained for 24 hours, and then subsequently treated in the manner 

 stated above for the safranin sections. 



Many other stains were tried, but with results in no way superior 

 to those already mentioned. Among these stains may be mentioned 

 haematin, dahlia, Flemming's triple stain and Heidenhain's modi- 

 fication of the Biondi-Ehrlich mixture. 



Literature. 



A complete historical review of the earlier investigations on this 

 subject has been so thoroughly and so frequently given by preceding 

 investigators, that it was thought best to omit one in this paper. 



For a complete bibliography, as well as an historical review of 

 such investigations, the reader is referred to the publications of the 

 following authorities: 



SoLBRiG 1872 (41), Hermann 1875 (17), Schultze 1879 (40), 

 Freud 1881 (12), Vignal 1883 (43), Nansen 1887 (25), Rawitz 

 1887 (31), Retzius 1890 (32), Binet 1894 (1) and Pflücke 1895 (30). 



All the publications which deal strictly with the topography of 

 the nervous system have been purposely omitted. 



Since 1887 several important publications have appeared which 



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