40 The American Geologist. January, 1904. 
The heads of the two radii, although showing none of the, 
excrescences or eburnations of rheumatoid arthritis are notice- 
ably flattened and expanded, presenting the appearance of a 
large head on a small nail. The disparity between the heads 
and necks is also shown by their measurements when com- 
pared with other bones. Thus while the average relation be- 
tween these two parts is as 24 to 15, or as 8 to 5, the necks of 
these two radii measuring but 11 mm. in diameter support 
heads of 22 mm. or twice their size. The margins of the 
acetabulum are sinuously curved but present no excrescences 
or erosions. 
The characteristic changes in detail are as follows : Parts 
of the bodies of two lumbar vertebrae show considerable flang- 
ing or expansion at their articular borders but no evidence of 
anchylosis. The several articular processes show no evidence 
of disease. The few remaining bodies of the dorsal vertebrae 
are also free from disease. The articular surface of the head 
of the metatarsal bone of the right great toe is prolonged 
backward, below. Slight lateral excrescences more distinct 
on the outer surface, are present along its margins. The mid- 
dle convex ridge is eburnated below. 
The knee-joint : The external condyle of the femur pre- 
sents a reflected flange of bone 4 to 8 mm. wide along its outer 
margin corresponding with a similar though somewhat more 
luxuriant outgrowth from the same margin of the external 
articular surface of the tibia. A distinct irregularity is also 
present at the posterior termination of the articular surface 
over which the tendon of the inner head of the gastrocnemius 
normally glides. The irregularity consists in a slight exuber- 
ance of bone at the upper margin with a distinct erosion and 
flattening of the articular portion. 
The surface is so irregular that definite lines of attrition, 
as presented in other portions of the surface can not be made 
out. It may possibly have been due to the presence of a sesa- 
moid bone in the tendon of the gastrocnemius, though an ap- 
parently reciprocal surface near the posterior margin of the 
articular facet of the tibia, ofifers the more probable explana- 
tion of its occurrence. 
At the juncture of the middle and posterior thirds of the 
articular surface, or at the place of bearing in semiflexion of 
