ON THE MUSCULAR ARCHITECTURE OF THE 

 VENTRICLES OF THE HUMAN HEART 



FRANKLIN P. MALL 



Professor of Anatomy, Johns Hopkins University, Baltimore, Md. 



TWENTY-TWO FIGURES 



The present study is to be considered as a continuation of 

 John Bruce MacCallum's, whose ill health prevented him from 

 continuing his work. MacCallum was a brilliant student, a man 

 of marked artistic temperament, whose untimely death has been 

 a very great loss to scientific anatomy. At the beginning of his 

 medical career, while he was yet a student of histology, he made 

 important observations on the histogenesis of the heart muscle 

 cell' which he believed to show that the main growth of the wall 

 of the ventricle takes place immediately under the endocardium, 

 — possibly in the Purkinje fibers. In order to give this ques- 

 tion a fuller test, he made a study of the growth of the sartorius 

 muscle," for it was thought that in this simple organ a key to 

 the growth of the muscle walls of the heart might be found. 

 Although the hypothesis regarding Purkinje fibres has proved 

 to be erroneous and although the study of the sartorius has been 

 found to be of little value in the study of the heart muscle, he did 

 succeed in unrolling the wall of the left ventricle into a single 

 sheet or scroll of muscle fibers.^ His presentation of the archi- 



^ J. B. MacCallum, On the histology and histogenesis of the heart muscle cell. 

 Anatom. Anzeiger, 13, 1897. 



2 J. B. MacCallum, On the histogenesis of the striated muscle fiber, and the 

 growth of the human sartorius muscle. Johns Hopkins Hospital Bulletin, 1898. 



^ J. B. MacCallum, On the muscular architecture and growth of the ventricles 

 of the heart. Welch Festschrift, Johns Hopkins Hospital Reports, vol. 9, 1900. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 11, NO. 3 

 MARCH, 1911 



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