NINTH ANNUAL REPORT. 147 
Deformities of the skull have not been noted by us, although 
the bones are found extensively softened and thickened. 
There is no question in our minds but that the degree of de- 
‘formity is dependent mostly on the amount of weight or pressure 
to which the individual bones are subjected, since, in the various 
parts of the body, all of them are found to show the essential 
pathological changes in about equal degree, though we believe 
that they are inaugurated in the lower extremities and spinal 
column. In the terminal condition any of the bones, even the 
petrous portion of the temporal bone, may be readily cut with 
a scalpel without previous decalcification. 
As a rule, where secondary injury is not present, the diseased 
bones present on their external surface very little indication of 
disease and none of inflammatory reaction. Periostitis occurs, 
we believe, only from some outside cause and generally the bone 
is smooth, though the epyphyseal ends appear symmetrically swol- 
len. The animals ordinarily evince little or no pain on pressure 
of the bone, even to the point of crushing it, for in a large pro- 
portion of cases the femurs, for instance, may readily be broken 
with the fingers. One must remember in this respect, however, 
that many of these animals do not appear to be very sensitive 
to pain from any cause. 
The gross appearance of the sectioned bone varies greatly. 
Generally the compact external plates are considerably thinned, 
the marrow space being considerably increased. As a rule, the 
outer shell presents a certain amount of lime salts and is still 
more or less hard, but in some cases, particularly near the epyphy- 
seal ends of the bone, it is found to be soft or semi-elastic, 
resembling in its physical attributes cartilage more than bone. 
The periostium shows no notable change in most cases. In the 
cases of the large flat bones, the entire thickness is transformed 
into an even greyish semi-cartilaginous material. 
The bone marrow also varies greatly in appearance; in 
places, usually in the shafts of the long bones, it is bright red 
in color and presents semi-solid areas resembling nodules of 
cartilage. In the epyphyseal ends, and sometimes throughout 
the shaft as well, the medulla is represented by a diffuse soft 
greyish mucoid material in which fine spicules of semi-cartila- 
ginous bone are found representing the normal compact frame- 
work of the marrow and cancellous portions. Where cartilage 
and bone are closely united, as over the head of the femur or 
between the vertebrae, the marrow seems to have extended into 
and replaced the cartilage to a large extent. Occasional cystic 
