250 KENJI NITTONO 



smaller in size than they are later. The nucleus, on the other 

 hand, is already large at birth and the chromatin well differ- 

 entiated. 



The so-called 'kernfaden' are to be seen very often. In the 

 next period at twenty days (figs. 4 to 6) the increase in the cell 

 body is much more rapid than the increase of the nucleus and 

 the Nissl bodies have increased not only in number, but in size 

 also. At this period the sections stain a deep violet or blue, 

 instead of a light violet, which color was common in the younger 

 material. This change in reaction appears not only in the Nissl 

 granules, but also in the ground substance of both the cyto- 

 plasm and the nucleus. These changes are to be seen in the 

 intermediate and in the smaller cells also which are found every- 

 where at this age. The interstitial tissues of the ganglion are 

 seen to be well developed, but are still immature, as can be told 

 from the well-stained nuclei and scantiness of the fiber substance. 

 Owing to the paucity of the interstitial tissue, the ganglion cells 

 are rather closely packed. 



The nucleus attains nearly its maximum size at the age of 

 about thirty-five days, as stated earlier. In this period no 

 special morphological changes of note were to be found either 

 in the cell body or in the nucleus, with the exception of the 

 increase in the size of the cell body and the nucleus. 



It should, however, be stated that there occur gradual and 

 progressive changes in all structures, such as a slightly deeper 

 stain of the Nissl bodies, the ground substance of cytoplasm, 

 etc., but no sharp lines can be drawn between the ages of twenty 

 and 485 days (figs. 4 to 12). 



Nissl ('94, '95), Lugaro ('96), Lenhossek ('97), Cox ('98), 

 Hatai ('01), and others have discussed the arrangement of the 

 stainable substance in the spinal ganglion cells according to the 

 size of the cell body, and I have attempted to classify various 

 forms of the ganglion cells in the gasserian ganglion by the same 

 method. 



]My own observations do not agree entirely with the descrip- 

 tion given by the authors just mentioned, but I am not ready 

 to discuss the matter at this moment, because my observations 



