DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 17 
96.7 per cent, and also lower than 93 per cent, the digestibility of beef 
tallow, which consists of both oleo oil and oleo stearin. 
In their reports of their physical condition during the test period, 
the subjects noted no unusual physiological conditions, 
OX-MARROW FAT. 
It is believed by many people that bone marrow possesses proper- 
ties which make it of particular value for food purposes and of 
especial value in the dietary of invalids and convalescents. That 
there is a scientific basis for such belief is shown by a review of the 
literature. In discussing the value of fat in the diet Friedenwald 
and Ruhrah x say that bone marrow, which is rich in fat, is used in 
the treatment of tuberculosis and pernicious anemia. The marrow of 
young animals is preferred, and the glycerin extract of bone marrow 
is utilized. Zink 2 states : " Yellow marrow contains chiefly fat which 
consists of olein, palmitin, and stearin, and which differs from the 
fat of the other parts of the body in having a higher acetyl equiv- 
alent." In a study of red marrow Forrest 3 obtained two proteins, 
one a globulin coagulating at 47-50° C, which contained no phos- 
phorus, and a second a nucleo-albumin which was found to contain 
phosphorus in its molecule. Glikin 4 reports that iron occurs regu- 
larly in beef marrow, the marrow of young animals containing larger 
amounts than that of old animals. According to Halliburton 5 the 
most important protein of red marrow " is a nucleo-protein which 
contains 1.6 per cent of phosphorus." In considering the dietary 
value of marrow, however, it must be remembered that it contains a 
large amount of marrow fat and that this, like all other fats, is a 
valuable source of energy in addition to the special therapeutic value 
attributed to it. Marrow is well known as food. Common examples 
are marrow bones, an old-fashioned dish, and marrow balls, which 
are served in soup. 
The preparation of marrow fat is confined very largely to the pack- 
ing houses, where it is obtained from the leg bones of beef animals. 
The process, according to information obtained from the Bureau 
of Animal Industry, is as follows : 
Marrow fat is prepared from long or shank bones, they being first heated in 
water at a temperature of from 160° to 170° Fahrenheit. Both ends of the 
bones are sawed off and the marrow removed by blowing with compressed air. 
1 Diet in Health and Disease. Philadelphia and London : W. B. Saunders Co., 1913, 4. 
ed., p. 144. 
2 Chem. Zentbl., 68 (1897), No. 5, p. 296. 
3 Jour. Physiol., 17 (1894-5), p. 175. 
*Ber. Deut. Chem. Gesell., 41 (1908), No. 5, p. 910. 
e Jour. Physiol., 18 (1895), No. 4, pp. 306-318. 
