GROWTH AND FATTENING 99 



insufficient food the fat was withdrawn to a marked degree from the 

 lean flesh of the body. 



The skeleton is not affected by poor nutrition until practically all 

 the fat has been removed from the fatty tissues and the muscles. In 

 the case of Steer III the withdrawal of fat had gone so far that nearly 

 all the fat had been removed from the marrow of the skeleton and re- 

 placed with water. Indeed, the marrow had practically disappeared and 

 in its place was a watery, ill-smelling liquid. This re-absorption of fat 

 takes place from all parts of the skeleton. In contrast with these changes, 

 the percentages of protein and ash were but slightly reduced, even in the 

 case of Steer III. 



In the process of fattening, the fat is laid on the body in a certain 

 order, being deposited first and most rapidly in certain regions, while 

 in others little is stored until fattening is well advanced. Waters states 

 that the withdrawal of fat from the tissues occurs in the reverse order 

 from which it was laid on that first deposited being the last to be 

 absorbed. 



As a result of these studies Waters points out that a young animal 

 may reach normal size by any or all of the following ways : 



1. By growing steadily from birth to maturity. 



2. By storing fat during a period of abundant food supply, which 

 will help to tide over a limited period of sparse food supply without 

 serious checking of growth. 



3. By prolonging the growth period. 



4. By an increase in the rate of growth during a period of liberal 

 feeding following a period of scanty feeding and low gain. 



5. By using its food more efficiently. Apparently when an animal 

 is kept for a limited period on scanty food, it gets on a more economical 

 basis than when liberally fed. A ration which is at first insufficient to 

 maintain an animal may be capable later of keeping the same animal at a 

 constant body weight, and still later of causing a small gain. If it be- 

 comes unthrifty due to partial starvation, it will then digest its food less 

 completely. 



138. Effects of checking growth. In the experiments at the Kansas 

 Station, Waters, Cochel, and Vestal studied the effect on pure-bred beef 

 steers of checking their growth for various periods by under-feeding. 

 They report that supplying a young, growing animal with a scant ration 

 for a short period only will have no permanent effect on its development. 

 Even when insufficient feeding is continued for a year or longer, the 

 animal will recover to a surprising extent when placed on liberal feed, 

 making unusually rapid and economical gains. Osborne and Mendel 47 

 have shown that while the normal growth period of rats rarely exceeds 

 335 days, those whose growth has been checked by insufficient food will 

 resume growth even at the age of 480 to 532 days. 



47 Jour. Biol. Chem., 18, 1914, pp. 95-106. 



