156 



THE SINO- VENTRICULAR BUNDLE. 



that the sino-ventricular bundle is not adult muscle. It should be noted in this 

 connection that as long as there is a complete muscular continuity between the 

 atria and ventricles in the embryo, ganglion cells are not visible in the heart; but 

 ganglion cells appear with the invasion of the atrioventricular ring by connective 

 tissue and the formation of the valves. In other words, before the definitive physi- 

 ologic reactions take place there are important morphologic changes, namely, the 

 appearance of cross-striations, of ganglion cells, and of nerves. 



Attention should again be called to the accessory muscular connections that 

 are found between the right atrium and ventricles. No experimentalist should 

 leave these out of consideration when interpreting the results of his findings. It 

 belongs to future anatomical researches to establish whether these connections 

 also have their origin in the sinus region of the heart or whether they are truly 

 atrioventricular fibers. 



To sum up, therefore, we have in the sino-ventricular bundle primarily a 

 growth center for the replacement of cardiac musculature. The cells begin their 

 growth in the sinus region of the heart and by a series of direct nuclear division 

 eventually reach the subendocardial musculature where they pass into cardiac- 

 muscle cells. Being embryonic in type they may retain their embryonic bipo- 

 tentiality of contractility and conductivity. The nerves which accompany the 

 bundle are associated with the vagus nerve as is the sinus tissue which it innervates. 



BIBLIOGRAPHY. 



AAGAAKD, O. C. and H. C. Hall, 1915. tiber Injektionen 

 des "Reizleitungssystem" und der Lymphgefasse 

 des Saugetierherzens. Anat. Hefte, 1 Abt., Bd. 

 51, p. 357-127. 



ASCHOFP, L., 1908. Uber den Glycogengehalt des 

 Reizleitungssystems des Saugetierherzens. Ver- 

 handl. d. deutsch. pathol. Gesellsch., p. 150-153. 



BENSELY, R. R., 1911. Studies on the pancreas of guinea 

 pigs. Amer. Jour. Anat., vol. 12, p. 297-388. 



BURROWS, M. T., 1912. Rythraical activity of isolated 

 heart muscle cells in vitro. Science, vol. 36, p. 90-92. 



CURRAN, E. J., 1910. A constant bursa in relation with 

 the bundle of His; with studies of auricular con- 

 nections of the bundle. Anat. Anz., Bd. 35, p. 89. 



DUESBERG, J., 1910. Les chondriosomes des cellules 

 embryonnaire du poulet, et leur role dans la 

 genese des myofibrils, avec quelques observa- 

 tions sur Ic d veloppement des fibres musculaires 

 striees. Arch. f. Zellf., Bd. 4, p. 602-671. 



ENGEL, IMGARD, 1910. Beitrage zur normalen und patho- 

 logischen Histologie des Atrioventricularbiindels. 

 Ziegler's Beitr. z. path. Anat., Bd. 48, p. 499-525. 



His, WILHELM, JR., 1893. Die Tatigkeit des erabry- 

 onalen Herzens und deren Bedeutung fur die 

 Lehre von der Herzbewegung beim Erwachsenen. 

 Arbeiten aus der med. Klinik zu Leipzig, p. 1449 



HOLL, M., 1912. Makroskopische Darstellung des atrio- 

 ventrikularen Verbindungsbiindels am men- 

 schlichen und tierischen Herzen. Arch. f. Anat. 

 u. Phys., Anat. Abt., p. 62-93. 



HOLMGREN, E., 1910. Untersuchungen tiber die mor- 

 phologisch naehweisbaren stofflichen Umset- 

 zungen der quergestreiften Muskelfasern. Arch, 

 f. mikr. Anat., Bd. 75, p. 240-337. 



KENT, A. F. S., 1893. Researches on the structure and 

 function of the mammalian heart. Jour. Physiol., 

 vol. 14, p. 233-254. 



1913. Observations on the auriculo-ventricular 

 junction of the mammalian heart. Quart. J. 

 Exper. Physiol., vol. 7, p. 193-195. 



MAC-CALLUM, J. B., 1898. On the histogenesis of the 

 striated muscle fibre and the growth of the 

 human sartorius muscle. Johns Hopkins Hosp. 

 Bull., No. 9, p. 208-215. 



MALL, F. P., 1915. Development of the heart. Refer* 

 ence Handbook of Med. Sciences, (Wood & Co., 

 3ed.), vol. 5, p. 58-64. 



MIRONESCO, THEODORE, 1912. Le chrondriome du 

 rfeeau de Purkinje du coeur. C. rend. Soc. de 

 Biol., t. 72, p. 30-31. 



MORRISON, ALEXANDER, 1912. On the innervation of 

 the sino-auricular bundle (Kent-His). Jour. 

 Anat. and Physiol., vol. 7, p. 319-327. 



PALADINO, Giov., 1914. Ancora per una questione di 

 priorita a proposito del fascio atrio-ventriculare 

 del cuore. Anat. Anz., Bd. 46, p. 90-94. 



RETZER, ROBERT, 1908. Some results of recent investi- 

 gations on the mammalian heart. Anat. Rec., 

 vol. 2, p. 149-155. 



TAWARA, S., 1906. Das Reizleitungssystem des Sau- 

 gethierherzens. Jena, G. Fischer. 



J. GORDON, 1909. The nerves of the atrio- 

 ventricular bundle. Proc. Royal Soc., ser. B, 

 vol. 81, p. 151. 



