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Physiology. — ^^On, tlw dcndoimicnt of tin- niijocanl in 7\'J('(Mf.s." 

 By Dr. .1. Ijoeke. (Coininiuiicated by Prof. T. Place.) 



During the last few years iiuicli attention has been giv^en to tlie 

 strnctnre of tlie lieart muscle, and several investigators have stated 

 the opinion, that the heart mnscle of the vertebrate heart is not 

 composed of definite cells, separated by clearly defined limits, but 

 that the heart muscle forms a syncytium, in which no cell l)()un(l- 

 aries can be recognised. For the embryonic heart this is sho\vn 

 most completely by Godlewski, independently from Godlewski, but 

 less fully l)y IIoyek and Heidenhain, confirmed and worked out 

 by Makceau. 



For the adult lieart (homo, mammalia) it has been M. Heidemiain^), 

 who has done most in this direction, and who has most strongly 

 urged (he conception of the heart muscle as asyjicytium. According 

 to him the septa, the "Treppen", the delicate lines standing at right 

 angles to the course of the myofibrillae, which are regarded by other 

 investigators as cell-limits, have nothing to do with real intercellular 

 structures (except perhaps from a i»]iylogenetic [)()iut of view); they 

 are ''Schaltstiicke", portions of the musclefibre which remained as it 

 were in an indifferent state, and i)lay a part in the process of longi- 

 tudinal growth of the fibres. For the still growing heart Heidenhain 

 draws the following conclusion: "dass die Schaltstücke ihrem urspriing- 

 liclien Verhalten nacli wachsende Telle sind. Telle, welche das 

 Langenwachstum besorgen und nach beiden Segmentenden hin das 

 Material fur die Angliederung neuer Miiskelfacher liefern" (1. c. 

 1901 Pag. 69). 



HociiE ') on the otiier hand takes these "Schaltstücke", for real 

 cellular limits, though incomplete. He maintains that the Schaltstücke, 

 the cement substance between the cells of the heart muscle, which 

 according to Eberth ') are homogeneous and after Biiowicz ^) are in 

 some cases homogeneous, in other cases composed of small rods 

 arranged parallel to each other, separate the cells of the myocard, 

 but only in the course of the myofibrillae. Between these "batonnets" 

 "le sarcoplasme qui remplit les interstices des fibrilles se continue 

 sans interruption apparente d'une cellule dans Tautre." The small 

 rods are lying just between the ends of the myofibrillae of the 



1) Anat. Anzeiger Bd. XVI 1899. Anat. Anzeiger Bd. XX 1901. 



~) Bibliogr. Anatomique 1897. 



•^) Arch, fur path. Anat. und Physiologie, Bd. 37. 



*) Virchow's Archiv. Bd. 139. 



