Williams, Fisher, and Udall: The Spavin Group. 13 
chlearis: the tendon over the navicular bone was extensively roughened. 
Posterior limbs: small nodular exostoses were found in the region 
of the tarsal joints; firm anchylosis of the cuneiform magnum and medium, 
the latter also anchylosed with the metatarsi. Cunean bursz obliterated, 
there being a firm union between the tendons and the bone. 
Case III.—A thirteen year old mare. Eight years ago she suffered 
from lameness of the anterior limbs, and although vigorous, stumbled 
frequently when driven. This condition was present up to the time 
of death. Disease of the hind limbs was not diagnosed during life. 
Autopsy; —Right anterior limb: scapulo-humeral articulation: car- 
tilage slightly roughened over the head of the humerus, it appeared to be 
roughened and thinner than normal. Carpus: cartilage covered with 
ulcer-like depressions between the upper row of bones and radius, small 
pieces of fibrous tissue floated in the depressions; slight lesions present on 
the distal end of the metacarpus. 
Right hind limb: femoro-tibial articulation: articular cartilage almost 
completely atrophied over the median trochlea of the femur; the latter 
bone was very porous at its distal end, the handle of a bistuory could 
easily be pushed into the osseous tissue for a distance of one and one- 
half inches. 
Left hind limb: femoro-tibial articulation: lesions allied to those 
found in the corresponding limb, the trochlea of the femur was less 
porous. 
Case IV.— Patient presented at the clinic April 3, 1900, when the 
following notes were made: age one year, diet four quarts of oats and 
ten pounds of hay daily. Patient to be treated for gonitis first noticed 
about April second, and from which the animal appeared to be very 
lame. Clinical examination’ revealed one gonitis, two spavins, and four 
ringbones. This animal was killed in December of the same year 
because of a chronic luxation of the patella. 
Autopsy: —Left hind limb: femoro-patellar articulation: synovial 
membrane distended with a large amount of fluid; extensive thickening of 
the capsular ligament; erosion of the external trochlea of the femur and 
roughness of the internal condyle. The external trochlea very compact, 
the inner soft and porous. Femoro-tibial articulation: the changes were 
similar to those in the preceding. Free bodies were found in the joint 
composed of bone, cartilage, and connective tissue. Histological examina- 
tion; the trabecule and osseous portions of the marrow cavities well 
marked, the latter containing many giant and lymphoid marrow cells. 
The giant cells were not all in direct contact with the trabeculz, some were 
situated in the middle of the marrow cavity. Tarsus: bones apparently 
normal; the cartilage exhibited small, punctiform, reddish-blue spots 
about two millimeters from the external margin of the articular 
surface. These correspond to those mentioned by other investiga- 
tors (“points of contact” of Eberlin). Upon a histological examin- 
ation of a section made through one of these points the following 
conditions were noted: the cartilage cells grouped in an irregula man- 
ner, their form more rounded and somewhat larger than in a like section 
of normal bone. An empty cavity was noted between the cartilage and 
