DESCRIPTIONS OF THE ILLUSTRATIONS 
Fig. No. 1— A, a broken ulna. 1 shows the diagonal fracture, with repair complete. 
Note the porous bony mass. 2, a splintered piece of bone which has been 
united to the main bone in the reparative processes. 
B, a broken tibia which has been repaired. 3, the fibula. 4, the tibia, 5, the 
point of fracture. 
C, a side view of A (smaller magnification). 
D, S, the fibula. 9, the tibia. 10, the point of fracture. The provisional 
callus has been largely absorbed. 
Fig. No. 2— A, a fracture of the metatarsus five days standing. Properly set. From a 
three-year-old S. C. Rhode Island Red hen. 1, the fracture. At this stage 
the exudate had not fully organized. 
B, fracture of the metatarsus thirteen days standing. From a one-year-old 
S. C. White Leghorn hen. Hen rather low in vitality. 1, the provisional 
callus. 2, the provisional plug. 3, the normal metatarsal wall at break. 
The bone shows a slight spring upon the application of considerable force. 
C, fracture of metatarsus thirteen days standing. From an eight-months-old 
S. C. Rhode Island Red cockerel. 1, the provisional callus at the point of 
fracture. 2, the provisional plug. 3, the normal metatarsal wall at point 
of the break. There was no spring when force was applied to this bone. 
Fig. No. 3— A, photograph showing the outside surface of fractured bones. 
B, photograph showing the inside surface of fractured bones. 1, fracture 
eight days standing. 2, fracture eight days standing. 3, fracture fifteen 
days • standing. 4 and 5, fracture twenty-one days standing. The latter 
two and first are vicious union, the second and third are properly set. 
Fig. No. 4—A photomicrograph of a section of the wall of the metatarsus of a cock. 
Fracture five days standing. 1, splintered fractured end. 2, the provisional 
callus. 3, the provisional plug. 4, the bone cells of the normal bone. 5, 
the endosteum. 6, the haversian canals. 
Fig. No. 5—An oblique fracture of thirteen days standing. 1, the fractured ends which 
have been placed in perfect apposition in the process of setting. 2, the 
provisional callus. 3, the provisional plug. 4, intermediate callus. 5, the 
periosteum, one of the sources of the new bone cells. 
Fig. No. 6—A rontgengraph of a normal tibia. 
•V 
Fig. No. 7—A rontgengraph of a fracture. Properly set. 
Fig. No. 8—A rontgengraph of a fracture of three days standing. Not properly set. 
Note the appearance of the provisional callus filling in the angles around 
the fracture. 
Fig. No. 9—A rontgengraph of a fracture of six days standing (same case as in No. 8). 
Note provisional callus. 
Fig. No. 10—A rontgengraph of a fracture of nine days standing (same case as in No. 
8). Note the increased density of the provisional callus. The density of 
the shadow depends upon the molecular density of the tissues. The molec¬ 
ular density of the callus becomes greater as reparative processes advance. 
Fig. No. 11—A rontgengraph of the same case at twelve days standing. 
Fig. No. 12—A plaster of Paris cast from a hen with a broken tibia. Slightly enlarged. 
Weight 55 grams. 
Fig. No. 13—A four-months-old S. C. Rhode Island Red pullet with a broken tibia. Prop¬ 
erly set, using splints (No. 1), cotton (No. 2), one-inch cotton bandage 
(No. 3), and glue. 
Fig. No. 14— A, a normal metatarsus of a cock. 
B, a repaired fracture showing an improperly set bone and a vicious union. 
