DEVELOPMENT OF DISCS, HEART MUSCLE OF PIG 343 
In conclusion, I wish to acknowledge my indebtedness to Prof. 
W. J. Baumgartner for his aid in obtaining material and for his 
very helpful suggestions and criticisms. 
BIBLIOGRAPHY 
1 Zimmermann, K. W. 1910 Uber den Bau der Herzmuskulatur. Arch. f. 
Mik. Anat., Bd. 75, S. 40. 
2 PanczewsKa, IRENE von 1910 Uber die Structur der menschlichen Herz- 
muskelfasern. Arch. f. Mik. Anat., Bd. 75, S. 41. 
3 WERNER, Marie 1910 Besteht die Herzmuskulatur der Sidugetiere aus 
alseits scharf begrenzten Zellen oder nicht? Arch. f. Mik. Anat., 
Bdat75,.5., 101. 
4 Jorpan, H. E. 1911 The structure of the heart muscles of the humming- 
bird, with special reference to the intercalated discs. Anat. Rec., 
Vole Ssap. old. 
5 MacCauium, J. B. 1897 On the histology and histogenesis of the heart 
muscle cell. Anat. Anz., Bd. 18, S. 609. 
6 Jorpan, H. E., anp Steete, K.B. 1912 A comparative microscopic study 
of the intercalated discs of vertebrate heart muscle. Am. Jour. 
Anat, vol: 43, p. 151. 
7 Jorpan, H. E., anp Banks, J. B. 1917 A study of the intercalated discs 
of the heart of beef. Am. Jour. Anat., vol. 22, p. 285. 
