BONE SOFTENING. 
39 
osteogenetic tissue, in which the blood-vessels are especially 
vulnerable by reason of deficient nutrition and toxic sub¬ 
stances in the circulation. 
In other cases, the lime salts are in abundance, but owing 
to a catarrhal condition of the intestines, they are not absorb¬ 
ed, hence do not reach the osseous tissue. According to Sal- 
kowski and Seeman, lime salts in excess have a similar effect, 
in that phosphate of lime combines with the chlorine of the 
blood, thereby producing a deficiency of chlorides. The re¬ 
sult of this is a deficiency of hydrochloric acid in the stomach, 
and by this means the solubility and absorption of lime salts 
are made impossible. 
We may still conceive that there exists, undiscovered as 
yet, in the blood a toxine which has the power of exciting in 
the bones the previously described methods of abnormal 
growth, osteomalacia. 
As a rule osteomalacia, does not, like rachitis, consist of a 
disturbance in development of bone, but the bones having 
already undergone normal development and hardness, after¬ 
wards become soft. Its true astiological factor has not yet 
been ascertained. 
It is especially frequent along the Rhine, in Westphalia, 
Flanders and northern Italy. This might point to some local 
infection in these localities which is yet undiscovered. 
Among the exciting causes, child-bearing is the most im¬ 
portant, for the disease usually dates from pregnancy. An¬ 
other factor which may be mentioned is unhygienic sur¬ 
roundings. The pathological process consists in a disappear¬ 
ance of the earthy salts of the bones, which begins usually 
from the medulla and extends outwards. The marrow is at 
first extremely hypersemic and extravasations of blood are 
frequently found. The bony structure surrounding the hav- 
ersian canals becomes converted into a soft, fibrous tissue ; 
the central cavity grows larger and larger and the cortical 
substance becomes as thin as paper. At this stage, the hy- 
persemia disappears and the marrow acquires a yellow color 
which may be entirely transformed into a yellow viscid fluid. 
The bones can now be easily cut with a knife; they possess a 
