617 



Conclusions. 



I. Ruptare of cardiac muscle fibres always occurs in relation to 

 the intercalated discs. 



II. The intercalated discs can not be interpreted as intercellular 

 structures. 



III. "Segmentation" and "fragmentation"' are, therefore, not to 

 be distinguished on the anatomical basis of ruptures occurring in 

 intercellular and intracellular portions of the heart muscle respectively. 



IV. As the heart muscle appearently possesses a syncytial struc- 

 ture, and as rupture of the fibres always occurs in relation to a single 

 structure (i. e. the intercalated discs), "segmentation'' and "fragmen- 

 tation" are probably the same process, exhibited in different degrees 

 of severity. 



Literature cited. 



Jordan: The Structure of Heart Muscle of the Humming Bird, with Special 



Reference to the Intercalated Discs. Anat. Record; Nov., 1911. Vol. 5, 



No. 11; 517—529. 

 Jordan and Steele: A Comparative Microscopic Study of the Intercalated 



Discs of Vertebrate Heart Muscle. Am. Jour, of Anatomy; May, 1912. 



Vol. 13, No. 2; 151—173. 

 Jordan: The Intercalated Discs of Hypertrophied Heart Muscle. Anat. 



Record; Sept. 1912. Vol. 6, No. 9; 357-362. 

 Hektoen: Segmentation and Fragmentation of the Myocardium. Am. Jour. 



of the Med. Sciences. 1897 ; cxiv ; 555—583. 

 MacCallum (J. B.): A Contribution to the Knowledge of the Pathology of 



Fragmentation and Segmentation, and Fibrosis of the Myocardium. Jour. 



of Exp. Medicine. 1899; Vol. 4. 409—424; plates xxi and xxii. 

 Renaüt (et Landouzy) : Note sur les alterations du myocarde accompagnant 



I'inertie cardiaque. Societe de Biologie; July 7th., 1877. 

 Obstreich: Die Fragmeutatio myocardii. Virch. Arch. 1893; Bd. cxxxiii. 

 Marceaü (F.): Recherches sur les bandes transversales scalariformes striees des 



fibres cardiaques. Compt. Rend. Acad. d. Sc, Paris; 1903; cxxxvi; 1685 



—1687. 

 Schlater: Einige Betrachtungen liber die sogenannte Fragmentation des Herz- 

 muskels. Centralbl. f. allg. Path. u. path. Anat.; Jena; xvi; 982 — 991. 

 Dietrich: Die Elemente des Herzmuskels. Jena, 1910. 



