124 EDWARD F. MALONE 



and finally disappear. After the disappearance of the small cells 

 the sjTnpathetic nucleus, consisting now entirely of the large 

 cells (fig. 1) proceeds caudally as a well developed and definite 

 group. In the most caudal portion of the medulla the sym- 

 pathetic nucleus is much reduced; only a few cells are seen in 

 each section, and these cells become smaller and have the appear- 

 ance of the smallest cell in figure 1 ; in this portion of the nucleus 

 (the caudal end) are probabl}^ also cells of the type shown in 

 figure 2, that is, similar to those in the oral portion of the nucleus, 

 but at present I cannot be absolutely sure of this, as the sur- 

 rounding cell groups have not been sufficiently studied. The 

 smallest cell shown in figure 1, is probably a transition type 

 between the other cells of figure 1, and those of figure 2. To 

 sum up, the sjTiipathetic vagus nucleus consists of three por- 

 tions: (a) an oral portion whose cells are of the type in figure 2; 

 (b) a middle portion whose cells are shown in figure 1; and (c) 

 a caudal portion composed of cells shown in figure 2 (same as 

 oral portion) and also of cells such as the smallest cell in figure 1 

 (probably a transition type). 



It is not my intention to present in this paper a detailed de- 

 scription of the types of cells in the vagus sympathetic nucleus, 

 but rather to point out the fact that there are very definite 

 differences in histological character between the cells of the vari- 

 ous groups; a study of the illustrations will make this evident. 

 Since these differences in cell character exist, and since such 

 differences must necessarily be an indication of corresponding 

 differences of cell activity, we may now consider whether these 

 different cell groups of different character may be brought into 

 relation with definite functions. In the first place, it has been 

 shown by Molhant, in his excellent and extensive work on the 

 vagus nerve, 'that the sympathetic nucleus of the vagus gives 

 origin to all the fibers of the ^-agus which supply smooth 

 and heart muscle, and that all its cells give origin to such 

 fibers. Further, he has shown that the oral portion sup- 

 plies smooth muscle (stomach, lungs), the function of the 

 extreme caudal portion is doubtful (possibly connected with the 

 trachea and bronchi), while the intermediate portion supplies 



