NUCLEUS CARDIACUS NERVI VAGI 125 



heart muscle, but he has failed to connect these different func- 

 tions with different types of cells. Concerning the function of 

 the caudal portion of the nucleus, which is composed of cells 

 of the type shown in figure 2, together with cells resembling 

 the smallest cell of figure 1, we can draw no definite conclusion. 

 The oral portion consists exclusively of the type of cells shown 

 in figure 2, and we may conclude that this type of cell supplies 

 smooth muscle; of course this does not justify us in concluding 

 that this type of cell (fig. 2) is the only type of cell which may 

 supply smooth muscle, or that this type may not in other regions 

 have a different function. Overlapping thecells supplying smooth 

 muscle (fig. 2) and extending caudally unaccompanied by other 

 types of cells is the type of cell shown in figure 1, and this por- 

 tion of the sympathetic nucleus has been shown (Molhant) to 

 supply heart muscle. 



It is evident therefore that the cells of figure 1 supply heart 

 muscle, while those of figure 2 supply smooth muscle (stomach 

 and lui^gs). In addition there is purely histological evidence to 

 support the functional relations of these two types of cells (figs. 

 1 and 2), since the cells supplying heart muscle (fig. 1) are a type 

 intermediate in histological structure between those supplying smooth 

 muscle (fig. 2) and those supplying striated muscle (cells of hypo- 

 glossiis nucleus, fig. 3). The relative size of the Nissl bodies in 

 the three types of motor cells illustrated in figs. 1 to 3 is espe- 

 cially worthy of notice. The fact that nerve cells supplying 

 heart muscle are of a type intermediate betw^een those supplying 

 striated and smooth muscle constitutes one of the strongest 

 arguments in support of the importance of the relation of cell 

 character to cell function, since heart muscle is histologically 

 intemiediate between the two other types of muscle. 



The cell group which supplies heart muscle, composed of the 

 characteristic cells shown in figure 1, I shall name provisionally 

 ''nucleus cardiacus nervi vagi." I do not feel justified in assign- 

 ing any name to the other portions of the vagus sympathetic 

 nucleus, but shall be content with pointing out that the cells of 

 the oral portion which supply smooth muscle are of a definite 

 type (fig. 2). A further division is at present not advisable 



