PLATES 



Magnification and optical equipment. Figures 1 to 7 inclusive and 10 to 14 in- 

 clusive, Leitz achromatic objective 6a, compensating ocular 6, X 500. Figures 

 8 and 9 Leitz achromatic objective 4, compensating ocular 6, X 300. Figures 15 

 and 16, Leitz apochromatic objective 2 mm., compensating ocular 6, X 1600. 

 All the figures were outlined with the camera lucida. 



Staining and thickness of sections. Figures 1 to 14 inclusive are from frozen 

 sections cut 30^ and stained with Herxheimer's Scharlach R. The fat droplets 

 shown in these figures by no means include all those found in the thickness of 

 the sections (30/x), but only such as fell within the depth of focus of the lens 

 employed. Figures 15 and 16 are from sections 3;^ thick stained by Bensley's 

 acid-fuchsin toluidin blue (mitochondria) method. 



ABBBEVIATIONS 



C, cardiac muscle fiber G, true interstitial granules (mito- 



D, dark cardiac muscle fiber chondria) 



L, light cardiac muscle fiber M, muscle column 



P, muscle fiber of bundle of His Z. Krause's membrane 



PLATE 1 



EXPLANATION OF FIGURES 



1 Transverse section of cardiac muscle from the left ventricle of an albino 

 rat kept without food for 96 hours (animal 23, table 2). The amount of fat in 

 the muscle fibers is very small. X 500. 



2 The same as figure 1 from an albino rat receiving protein, carbohydrate 

 and a small quantity of fat (animal 10, table 1). The amount of fat in cardiac 

 fibers is small. X 500. 



3 The same as figures 1 and 2 from an albino rat fed as in figure 2 (animal 

 6, table 1). Moderate amount of fat in the muscle fibers; L, 'light' cardiac fibers; 

 D, 'dark' cardiac fibers. X 500. 



4 The same as figures 1, 2 and 3 from an albino rat, killed twenty hours after 

 consuming 8 or 10 grams of pork fat (animal 46, table 3). The amount of fat 

 in the cardiac fibers is large; L, 'light' fiber; D, 'dark' fiber. X 500. 



5 Longitudinal section from same preparation as in figure 4; L, 'light' fibers; 

 D, 'dark' fibers (animal 46, table 3). X 500. 



6 From the interventricular septum of a cat killed 17 hours after receiving 

 a large meal of pork fat (animal 84, table 5). Very large amount of fat in cardiac 

 fibers, C; moderate or large amount in Purkinje fibers of the left limb of bundle of 

 His, P. X500. 



7 From the interventricular septum of an eight months' human fetus (animal 

 141, table 8). There is a moderate amount of fat in the cardiac fibers, C, and also 

 in the Purkinje fiber of the left limb of the bundle of His, P. X 500. 



8 From the interventricular septum of the heart of a woman aged 53, fatal 

 lobar pneumonia, cardiac fibers, C, contain a moderate amount of fat; fibers of 

 left limb of bundle of His, P, show a very large amount of fat. X 300. 



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