44 Jcninial of Comparative Neurology and Psychology. 



For instance, as I have already mentioned, in an earlier stage of 

 the cell life, the first Nissl granules are derived from the nucleus 

 either by diffusion or extrusion, some of them changed, while 

 others remain unchanged. The changed granules are utilized 

 in part for the formation of the cytoplasm and in part during 

 this process are returned to the nucleus or excreted as waste. 

 While in the adult nerve cells, the dissolved nucleins are trans- 

 formed into the Nissl granules, ground substance, pigment, 

 oxyneutrophile granules (Marinesco, '02), amphophile gran- 

 ules (Olmer, '01), neurosomes (Held, '95), etc. All the 

 structures given above differ from one another morphologically 

 as well as chemically, thus indicating that the nucleins in the 

 nucleus, after they have been brought into the cytoplasm are 

 transformed there. This corresponds with the scheme of Ver- 



WORN. 



Summary. 



The following is a summary of the main facts given above : 

 (i) At a very early stage of the spinal ganglion cells of the 

 ~white rat, pseudopodia-like processes are formed from the nu- 

 cleus and extend towards the protoplasmic process. The mem- 

 brane of the pseudopodia is perforated. 



(2) Through these perforations the astral rays of the cen- 

 trosome, which lies near the nucleus and is enclosed by the 

 pseudopodia, penetrate into the nucleus and become continu- 

 ous with the linin network. 



(3) The Nissl granules, when first formed, are derived 

 either by the diffusion of the nucleins from the nucleus or by 

 a migration of the accessory nucleoli into the cytoplasm. 



(4) The materials for the formation of the nuclein are ab- 

 sorbed into the nucleus by means of the pseudopodia. These 

 materials are collected from the periphery of the cell body to 

 the center of the centrosome by means of the astral rays 

 and then again through these rays they are conveyed toward 

 the pseudopodia. 



(5) At an advanced foetal stage, as well as in the adult, 

 the nucleins are enclosed within the nucleus in a dissolved con- 



