324 CHESTER A. STEWART 
The weight of the ligaments and periosteum (obtained by sub- 
tracting the weight of the moist cartilaginous from the weight 
of the liganientous skeleton) apparently has decreased consider- 
ably in the test rats at three, six and ten weeks of age. For the 
last group there is an apparent loss in weight from an average 
of 5.12 per cent of the body weight in the controls, to an 
average of 3.04 per cent in the test rats. The data for the 
ligaments and periosteum at the end of the very long fast- 
ing periods are variable, but in the majority of instances there 
is an indication of an increase in the weight of this portion of 
the skeleton. 
Jackson (’15 b) in similar experiments starting at three weeks 
of age, found the ligamentous skeleton to manifest a marked 
growth tendency during maintenance. 
The alkaline solution in which the skeletons are boiled probably 
acts more severely on the tender skeletons of my young controls 
than on the tougher and more calcified skeletons of the older test 
rats, thus giving an abnormally high apparent weight for the 
ligamentous portion of the skeleton in the controls. This would 
no doubt tend to mask any actual increase in the ligaments and 
periosteum in the rats underfed for the shorter periods. This 
may account for the difference between my results in earlier 
periods of fasting and those obtained by Jackson for the liga- 
mentous structures. 
In the case of the dried cartilaginous skeleton the data (table 1) 
indicate a greater percentage of dry substance in the skeletons 
of the test rats than in the controls. At ten weeks of age the 
percentage of dry substance amounts to 23.4 per cent of the 
moist cartilaginous skeleton in the controls and 30.3 per cent 
in the test rats. Also at other periods (both older and younger) 
the percentage of dry substance in the skeletons of the test rats 
exceeds that for the controls. 
It is evident, therefore, that during the underfeeding the 
skeleton had gained in solids and lost in water content. Thus 
the continued growth of the skeleton had proceeded along the 
lines of normal development, for Lowrey (718) finds the dry 
substance of the normal ligamentous skeleton to increase steadily 
