168 Prof. A. B. Macallum and Miss M. L. Menten. [July 24, 



parts of the affected extent gradually becoming less distinct. Frequently 

 also axis cylinders were found wholly unaffected, and these would alternate 

 with deeply striated fibres. When the coloration became marked the 

 striation was indistinct. The minutest as well as the broadest fibres 

 exhibited the striae. The material constituting the matrix of each stria did 

 not appear to be different from that between the coloured bands, and both 

 series varied in breadth even in the same fibre. In parts of certain axis 

 cylinders the striae were constituted of granules and where striae were 

 not present the granules were sometimes regularly, sometimes irregularly, 

 arranged with, amongst them, longitudinal fibrillae. 



Frommann found also that the nerve cells of the spinal cord, on treatment 

 with nitrate of silver, took a light or deep brown, sometimes a grey-blue 

 colour which increased with time. The nucleus in such preparations was as 

 dark as, or lighter than, the cytoplasm, while the nucleolus was as dark as, or 

 darker than, the cell. 



The next observer, Grandry,* who studied the action of nitrate of silver 

 on nerve elements, corroborated Frommann in many of the above-mentioned 

 details, and dealt specially with the striae which are now henceforth known as 

 Frommann's lines. The position of these could be altered by pressure but 

 they could not be destroyed by such means. He claimed that by keeping the 

 preparations for a long time in glycerine the striae could on compression be 

 completely isolated. There were, in his opinion, two substances in the axis 

 cylinders not mixed or diffused in each other, but wholly distinct, and he 

 compared the structure they present to that found in striated muscle fibre. 



Grandry found a very marked striation in the cell body and polar 

 processes of nerve cells of the spinal cord. These striae varied in diameter 

 even in the same cell, and there was a variation also in their quality, some, 

 the finest, being completely homogeneous, while others were of granular 

 composition. Grandry found at times, as Frommann did, the body of the 

 eell to colour uniformly brown, but the nucleus was unstained. In other 

 cases a portion of the cell body exhibited the striae while the remainder was 

 uniformly coloured. 



This work of Grandry was done in Schwann's! laboratory, and that 

 observer, in discussing Grandry's results, remarked that " it seemed difficult 

 to admit that formations so regular, like the striae in question, could be 



* " Recherches sur la Structure du Cylindre de I 5 Axe et des Cellules Nerveuses," 

 'Bulletins de lAcademie de Bruxelles," 2nd Series, vol. 25, 1868, p. 304; also "De la 

 Structure intimedu Cylindre de l'Axe et des Cellules Nerveuses," ' Journ. de TAnat. et de 

 la Physiol.,' vol. 6, 1869, p. 289. 



t 'Bulletin de TAcad. de Bruxelles,' 2nd Series, vol. 25, 1868, p. 287. 



