262 THE HEART, BY F. SCHWEIGGER-SEIDEL. 



be exhibited, which might be regarded as nervous in their 

 nature, even without any direct connection with undoubted 

 nerve fibres being discoverable. Such fine fibrils sometimes 

 adhere firmly to the muscle cells. 



Notwithstanding the doubts that exist on some of these 

 points, it may be regarded as well ascertained that the finer 

 branches of the cardiac nerves lie between the proper elements 

 of the muscle, and so come into immediate contact with the con- 

 tractile substance which is here destitute of sarcolemma. As to 

 what proportion the number of terminal nerve branches bear to 

 the number of muscle elements, no positive statement can at pre- 

 sent be made. I have not been able to observe any such direct 

 connection between the nerves and the nuclei of the muscle 

 cells as has been stated by Frankenhauser in regard to the 

 smooth muscles.* 



It still remains to notice other parts in which ramifications of 

 the cardiac nerves occur, and of these the first that may be men- 

 tioned is the pericardium, in which, as in other serous membranes, 

 networks of fine fibres are present. And, secondly, the endo- 

 cardium, in which a very considerable development of nervous 

 tissue exists. This distribution is not exclusively connected 

 with the presence of muscular layers, since, besides motor, we 

 must certainly admit the existence of other nerves with dif- 

 ferent endowments. The latter terminate in the inner laminse 

 of the membrane ; but their finer branches, in consequence of 

 the elastic tissue present, are only to be discovered with 

 difficulty, and require the application of chloride of gold.f 

 They are nucleated, and form networks in the membrane which 

 are analogous to those ordinarily found in serous membranes, 

 except that the meshes are much narrower. Since, however, 

 there is no regularity in their distribution, any attempt at 

 comparative measurement would only be applicable to special 



* To enter more minutely on this subject, and to give the details required 

 for making special investigations in it, would lead us too far, and the con- 

 sideration of these points must therefore be reserved for discussion else- 

 where. 



t The above statements are based on hitherto unpublished investigations 

 that have recently been made under my direction by Dr. Schmulewitsch. 



