Hatai, Spinal Ganglion Cells. 31 



basic dyes (Figs, i, 5). This indicates that the thicker por- 

 tions contain an accumulation of the nucleoproteid. This state- 

 ment is supported by the fact that the preparations tested for 

 iron show this area deeply stained (Fig. 2). The accumulation 

 of the nucleoproteid along the part of the nuclear membrane 

 which turns towards the process is a highly interesting phenom- 

 enon since it bears on the problem of the cell metabolism. 

 This point will be discussed later on in detail. An accumula- 

 tion of the nucleoproteid is frequently visible along the outer 

 surface of the nuclear membrane as is shown in Fig. 3. 



These pseudopodia-like processes of the nucleus are inti- 

 mately related to the rays of the centrosome. The centrosome 

 in nerve cells has been described by several investigators, and 

 in the nerve cells of the white rat in both adult and young it 

 has been described by the present writer ('01). Although some 

 investigators deny the existence of the centrosome in the nerve 

 cell, the structure is so definite and so clear that in properly pre- 

 pared sections, its presence can not be disputed. The centro- 

 some is especially clear in the case of the embryonic cells and 

 every minute feature of the organ may be distinguished. As a 

 rule, the centrosome lies very near the nucleus and in the con- 

 cavity formed by it (Figs, i, 2, 3, 4, 5). The centrosome is 

 composed of two minute central corpuscles surrounded by still 

 more minute granules (centrosphere). These granules arrange 

 themselves in straight lines which run from the center towards 

 the periphery radially (astral lines). The astrosphere is clearly 

 •distinguished from both surrounding cytoplasm and centro- 

 sphere, since it stains very lightly with iron-haematoxylin owing 

 to a lack of the Nissl granules. By overstaining with 

 acid dyes, however, astrosphere stains a more intense red than 

 the surrounding substance. The minute structure of the cen" 

 trosome in the nerve cells of the white rat has been reported 

 already by the writer ('01) and therefore, with the exception of 

 the astral structure, it need not be further described here. The 

 astral rays which start from the centrospere run radially towards 

 all parts of the cell body. Those rays which runs towards the 

 nucleus extend not only as far as the nucleus but penetrate its 



