245 



»^. A 



So far as could be ascertained the nerve cells lie on the muscle 

 fibers of the heart, between them and the pericardium. When the 

 wave of contraction passed over the heart the nerve cells could be 

 seen to move with 

 the muscle fibers. At 

 the point where the 

 nerve cells are found 

 the pericardium is 

 closely applied to 

 the heart muscle, 

 making it very diffi- 

 cult to get the exact 

 relation of parts. 

 Long and careful 

 study of serial sec- 

 tions of material put 



Fig. 3. Optical sec- 

 tion of anterio-dorsal end 

 of heart of Molgiila man- 

 hattensis after treatment 

 with methylen blue. Oc. 3 

 X Vi2 Im™- Leitz. Re- 

 duced Yj- ^- '• connec- 

 tive tissue fibers, e. dor- 

 sal edge of heart, g. c. 

 ganglion cells, n.f. neiTC 

 fibrils. 



-Fi^- 3 



up in Flemming, Hermann, and Vom Rath and stained in iron 

 haematoxylin have failed to clear up this point completely. Groups 

 of cells, the nuclei of which presented the characteristics of those of 

 nerve cells, have been found at about the point already designated. 

 These cells were closely applied to the heart wall, the pericardium 

 and heart proper having merged at this point. 



In some preparations with methylen blue nerve fibrils have been 

 followed from the heart for a little distance dorsally toward the ovary. 

 A fairly large nerve trunk has been observed near the endostylar end 

 of the heart probably a continuation of the dorsal nerve cord, but no 

 connection was proven either with it or the heart ganglion. Much 

 physiological experimentation mitigates against this connection. 



Physiological research on the action of the heart of Sal pa ac- 

 cording to ScHULTZE, shows the ability of any part of the heart to 

 originate a series of rhythmic contractions. Lingle finds in the heart 



