42 



components having, their ori^'ifi here innet-vtite viscera.. 



The nucleus is composed of quite large neurones. The only 

 larger ones in the oblongata are the gigantic tract-neurones 

 described in Subsection 3, a. The cells are arranged in a com- 

 pact cluster, as seen in transverse section, and this is tra- 

 versed during a part of its course by the fasciculus communis. 

 Pig.?, v.m.n., illustrates the disposition of the neurones 

 and their characteristic forms. 



The cell-body has its form influenced by the number of 

 its dendrites, ranging from triangular to stellate. The den- 

 drites are always several in number. They are massive proc- 

 esses, often arising through such wide bases that it is diffi- 

 cult to say A'here the line of demarcation between dendrite 

 and cell-body should be drawn. The dendrites branch freely, 

 and the closeness with which the neurones are arranged gives, 

 therefore, a most complicated tangle of interlacing branches. 



The internal organization of a viscero-motor neurone is 

 represented in Fig. 47. The nucleus is central, or only slight- 

 ly eccentric, and it has an evenly rounded contour. The nucle- 

 olus is large; there is rarely a subsidiary nucleolus. The 

 nuclear reticulum has a coarse mesh which exhibits great clots 

 or lumps of chromatin at the points of intersection. 



The cytoplasm contains tigroid-bodies of various sizes. 

 The largest masses lie in the field of the nucleus. The ones 

 next to the nuclear membrane may assume the form of nuclear 

 caps. At the periphery of the cell, the prevailing form of 



