84 CM. JACKSON 



EXTREMITIES AND TRUNK 



The extremities were separated from the trunk at the shoulder 

 and hip-joints, respectively. From figure 1 and table 3 it is seen 

 that the /ore limbs fbrmed an average of 7.2 per cent of the body 

 in the acute inanition series, and 6.9 per cent in the chronic 

 inanition series. According to Jackson and Lowrey ('12), in the 

 normal adult rat the fore limbs form about 5 per cent of the 

 body. Consequently it would appear that there has been a rela- 

 tive increase in the weight of the fore limbs during inanition, 

 especially during acute inanition. This increase is greater than 

 would be expected, since (as will appear later) the skeleton is 

 the only important constituent of the limbs which increases in 

 relative weight during inanition, the integument and musculature 

 remaining relatively constant. The conclusion as to the fore- 

 limbs should be regarded as uncertain, however, because of: (1) 

 the difficulty in separating the limbs (especially the skin) in a 

 uniform manner; (2) the comparatively small number of observa- 

 tions upon which both the normal and the experimental average 

 is based; (3) the apparent lack of agreement between the results 

 for the entire fore limbs and for their components, skin, skeleton 

 and musculature. It is possible, on the other hand, that the 

 losses for skin, skeleton and musculature are not uniform in all 

 parts of the body. Chossat ('13) has shown, for example, that 

 the great pectoral muscles in pigeons lose relatively much more 

 than the remainder of the musculature during inanition. 



The hind limbs (fig. 1 ; table 3) in the normal adult form about 

 15 per cent of the body (Jackson and Lowrey). As might be 

 expected, this is slightly increased, to 17.5 per cent, in the acute 

 inanition series, probably on account of the relatively heavier 

 skeleton. In the chronic inanition series, the hind hmbs average 

 15.3 per cent, or about the same as normal. This may be 

 explained as due to the relatively greater loss in the integument 

 and musculature during chronic inanition (as will be shown 

 later), this loss tending to counterbalance the relative increase 

 in the skeleton. 



The trunk (fig. 1; table 3) is measured by substracting the 

 weight of the head and extremities from the net body weight. 



