736 FRANCIS H. McCRUDDEN 



bone laid down may become chemically and physically abnormal. Thus, 

 in tabetic patients, when the arc jfor deep reflexes from the knees 

 becomes broken, one of the results may be a Charcot joint, one feature of 

 which is an osteoporosis, with a complete loss of the normal architectural 

 features of the adjacent bones. In cerebral palsies, poliomyelitis, tabes, 

 and syringomyelia, we often see rarefaction and atrophy of bone (Hunt, 

 Stewart). In various myopathies, the long bones of the limbs correspond- 

 ing to the affected muscles undergo rarefaction and atrophy, and the nor- 

 mal ridges for muscular attachments become smoothed down (Merle and 

 Raulot-Lapointe) . We have evidence of bone metabolism also in the dis- 

 use atrophy and rarefaction, so frequently observed in roentgenograms of 

 patients, with a limb immobilized in plaster, and in patients with wasting 

 diseases, and in the bone softening seen in the enfeebling diseases influ- 

 enza, visceroptosis (Barker(a)). Acute bone atrophy demonstrable in 

 X-ray plate is very common. 



A generation ago, Pommer(a) pointed to the presence of osteoblasts 

 in bone at all ages as evidence of continuous bone metabolism, and Tomes 

 and Morgan offered such evidence more than two generations ago. 



We have evidence of active bone anabolism in the formation and sub- 

 sequent calcification of the callus following a fracture. 



Active bone catabolism is seen during starvation. Thus, it was shown 

 that the professional fasters, Cetti and Breithaupt, after a week to ten 

 days of starvation, were excreting nearly as much calcium per day as in 

 the beginning (Lehman, Muller, Munk, Senator and Zuntz(fe)). The 

 amount of flesh catabolized could be calculated from the amount 

 of nitrogen excreted; and, the amount of calcium in flesh being 

 known, it could be shown that the amount lost was more than could 

 be accounted for, unless it was assumed that it came from the bones. 

 Similar calculations from figures obtained by Benedict (d), on a man 

 who starved thirty-one days, show that 93 per cent of the calcium excreted 

 must have come from the bones. Munk's(a) and Muller's studies of 

 starving dogs show the same thing. Forster(fr) fed a dog a diet 

 poor in calcium for twenty-six days. In that time the dog lost 13.57 

 grams calcium over and above that taken in the food. Analysis of the 

 different organs demonstrated that this must have come chiefly from 

 the bones. 



Besides such metabolism experiments we have direct analysis of the 

 bones showing that the mineral constituents are used up during starvation. 

 Voit's experiments (a), which were the first to show that the bones 

 lose weight during starvation, cannot be used as evidence because he did 

 not show that the mineral constituents decrease. Weiske's(rf) negative 

 results, in the case of starving dogs, are likewise inconclusive, on account 

 of the short duration of the experiments (seven to eleven days). Sedlmair 



