A STUDY OF THE DIAMETERS OF THE CELLS AND 

 NUCLEI IN THE SECOND CERVICAL SPINAL 

 GANGLION OF THE ADULT ALBINO RAT. 



BY 



SHINKISHI HATAI, Ph.D. 



(^Associate in Neurology, The Wistar Institute.) 



From The Wistar Institute of Anatomy and Biology, Philadelphia. 



With Four Figures. 



INTRODUCTION. 



It is generally believed that the spinal ganglion contains sev- 

 eral types of nerve cells which can be morphologically differen- 

 tiated from one another. The varieties of cells whose existence 

 in the ganglia have been repeatedly confirmed are: ( i ) cells with a 

 T- or Y-shaped division of the processes. Such cells are consid- 

 ered to be most abundant and to be both large and small in size. 

 (2) Dogiel's cells of second type, multipolar cells, and (3) multi- 

 polar cells which resemble in shape and structure sympathetic 

 ganglion cells. The most complete classification is based on the 

 study of methylene blue preparations. In a general way the pres- 

 ence of the several varieties of cells in the ganglia mav also be 

 demonstrated in ordinary paraffine sections treated with any of 

 the basic dyes followed by a counter-stain. In such preparations 

 one can easily distinguish cells of different sizes as well as those 

 exhibiting different arrangements ol the stainable substance. 

 These two characters, size and arrangement of stainable substance, 

 have been used as a criterion by several investigators in order to 

 classify these cells. 



By this method Lugaro ('96) distinguishes in the dog five 

 different varieties of the spinal ganglion cells, Lenhossek ('96) 

 in the human spinal ganglion distinguishes three varieties, Cox 

 ('98) in the spinal ganglion of the rabbit, two main varieties, 

 and the author ('01) using the same criterion has distinguished 

 three varieties in the spinal ganglion of the albmo rat. It is my 



