No. 3-] NERVOUS SYSTEM OF CYNTHIA PARTITA. 113 



It is well known that, in early life at least, the ganglion cell 

 is migratory. Such a cell is shown in Fig. 3. It has wandered 

 out from the ganglion (shown in next section), and is probably 

 on its way to the periphery. This cell is observed to contain 

 two centrosomes. It is worthy of note that in the mammalia 

 the only ganglion cells in which centrosomes are found (so far 

 as known) are those of the spinal and sympathetic ganglia. 

 The cells of the spinal ganglia have probably migrated from the 

 central system; the cells of the sympathetic are proved to have 

 migrated from such a source. In the spinal cord cells border- 

 ing the central canal migrate out into the cord. These cells 

 are the neuroblasts. The above facts seem to prove that the 

 ganglion cell in certain stages of its existence has the power 

 of locomotion. Might not the centrosome preside over the 

 locomotor power of the cell — in the ganglion cell as well as 

 in the leucocytes .'' 



The theories of Englemann and Cajal, in regard to the move- 

 ment and growth of the ultimate ends of the cell process, are 

 interesting from this standpoint. According to these authors, 

 the cell processes are capable of growth and may branch, form- 

 ing more and more complex endings. These endings may at 

 one time be in connection with one set of cells, at another time 

 with another set, thus giving many new pathways between 

 different cell groups at different times. Here again is the idea 

 of movement of parts of the cell. Could the centrosome influ- 

 ence such movement } Would such movement, if it existed', be 

 homologous or analogous to the movement in pigment cells .'* 

 Such questions cannot yet be answered. 



This suggestion in regard to the possible function of the 

 centrosome in the ganglion cell must not be taken for fact or 

 theory. It is only suggestion. Much more work must be done 

 and many more facts gathered before such a view could be 

 taken for a theory. But it is hoped that at some future time 

 the problem may be successfully attacked and solved. 



