WEIGHTS OF ORGANS IN UNDERFED YOUNG RATS 127 



the average is slightly lower. In the six to thirty-two weeks 

 experiment, the musculature appears very slightly higher than 

 in the controls at six weeks, while in the ten to thirty-five weeks 

 experiment, the musculature appears slightly lower than in the 

 con^trols at ten weeks. In the latter case, however, the controls 

 are too heavy for comparison with those under experiment. 



In general, it seems clear from the foregoing that in young 

 rats held at constant body-weight the musculature also remains 

 nearly constant in weight, with perhaps a very slight tendency 

 to increase in the m^tjority of cases. In the course of normal 

 growth during this period, the musculature shows a more rapid 

 growth than any other system, increasing from about 27 per cent 

 of the body at three weeks to 41 per cent at ten weeks of age 

 (Jackson and Lowrey). During inanition in adult rats, the 

 musculature loses approximately in proportion to the entire body, 

 slightly less in acute inanition and slightly more in chronic 

 inanition (Jackson '15 c) 



Aron ('11) did not weigh the muscles in his experiments on dogs, 

 but infers (p. 29) that: ''Only the flesh, muscles and fat of the 

 body remain as the tissues which must have lost during the course 

 of the experiments." From an analysis of samples taken from 

 the leg muscles, he also concludes that ''The muscles contained 

 only one-half of the normal amount of solids," the protein being 

 greatly decreased and the water-content increased. Again, 

 however, his comparison is with controls at the end rather than 

 the beginning of the experiment, so that no conclusion can be 

 drawn as to the changes taking place during the experiment in 

 the animals held at constant body-weight. 



VISCERA AND 'REMAINDER' 



With the visceral group (table 9; fig. 4) have been included the 

 brain, spinal cord and eyeballs, as well as the thoracic and 

 abdominal viscera. According to Jackson and Lowrey '12, this 

 group decreases from about 21 per cent of the body at three 

 weeks to about 16 per cent at ten weeks of age. This is in fairly 

 close agreement with the controls in the present series, except at 



