14 H. HAYS BULLARD 



four individual rats of this group were fed as follows: four, 

 olive oil; seven, pork fat; ten, egg yolk; thirteen, butter. Fif- 

 teen individuals of the group have a moderate amount of fat 

 in the myocardial fibers, as in figure 3, while nineteen have a 

 large amount as in figure 4. The cardiac fibers of the rats in 

 this group contain an unusual amount of neutral fat due no doubt 

 to the fatty character of the food. The animals would eat but 

 sparingly of olive oil and the effect produced was less marked 

 than in the case of butter and pork fat which were eagerly 

 consumed. A number of rats (nos. 48, 49, 57, 58) would eat 

 but 'little fat after the first few days and the fat content of 

 the myocardial fibers was no more than in animals living on 

 carbohydrates and protein. Figure 4 represents a transverse 

 section of ventricular fibers from a rat (no. 46) which was 

 killed twenty hours after consuming eight or ten grams of 

 pork fat. The cardiac fibers are loaded with droplets. As will 

 be seen from table 3 the large amount of fat makes its ap- 

 pearance in the heart with astonishing rapidity, reaching a 

 maximum in from twelve to twenty-four hours after but one or 

 two large feedings of a fatty food. Even when a fatty diet is 

 continued for as long as twelve or fourteen days the amount of 

 fat in the cardiac fibers is no more than after a single large fatty 

 meal, although the animal may show a marked increase of adi- 

 pose tissue. 



Figure 4 may be taken as representative of the fat fed group, 

 just as figure 1 was considered representative of the inanition 

 group and figure 3 of the normally fed group. It is quite clear 

 that the cardiac muscle fibers of the rat normally contain a very 

 considerable quantity of fat in a microscopically visible form. 

 Also in inanition the normal quantity is diminished almost to 

 the point of complete disappearance while in animals on a fatty 

 diet the cardiac fibers are usually loaded with droplets. 



Cats. Table 4 shows a group of normal cats which were fed 

 for three to ten days on a well balanced ration of bread, milk and 

 moderately fat boiled beef. Of the twenty animals in this group 

 eleven have a moderate amount of fat in the cardiac fibers 

 (similar to fig. 3), six have a large amount (similar to fig. 4), 



