THE SKELETON AND ITS JOINTS 367 
extent by the calcium ingested, and that when the diet was 
poor in this element, the output materially exceeds the 
intake, a fact which is immediately changed where the 
animal is put on a diet high in calcium. So far as we could 
find there are no studies on the mineral metabolism of 
beginning cases of Paget 's disease. It seems possible 
from the osteomalacic animals previously studied, that the 
low mineral and otherwise faulty content of the diet might 
so disturb the chemical equilibrium directly, through the 
neurotrophic mechanism or through the perversion of the 
ductless glands, that the mere addition of lime water 
might entirely change the pathological picture. This is in 
accord with the histology. The initial histological pic- 
ture is always resorption of bone, a general decalcification 
which later presents an irregular proliferation. The 
disease then progresses along different lines ending as 
osteitis fibrosa cystica, Paget 's or Von Recklinghausen's 
diseases, etc., dependent upon the strength of the repara- 
tive stimulus and the organism upon which it acts. 
'' These cases are of interest (1) because they are typi- 
cal examples of Paget 's disease as it has been described 
in man both clinically and pathologically, (2) because the 
disease shows the same general type of inorganic metab- 
olism that was exhibited in man, (3) because of the alkali 
hunger shown by one monkey, and by two human cases, a 
hunger which was severe, which preceded the deformity 
and disappeared after the deformity was established, 
(4) because the disease developed in animals fed on a diet 
insufficient in its inorganic and vitamine content to which 
an excess of calcium was added. 
'' From this study it seems possible that Paget 's 
disease may be just one stage in a deficiency disease, a 
reparative response through a neurotrophic mechanism 
or through the perversion of the glands governing calcium 
metabolism which has been perverted by an improperly 
balanced diet." 
