9 
The Bulletin 
and a swelling, shortening, or crepitus. In handling the part the feeling 
of the sense of crepitus is a diagnostic symptom. 
If the fractured ends glide past each other, the contraction of the 
muscles may cause a shortening of the limb. The muscles of the fowl 
are loosely connected by fascia and displacement of the fractured ends 
of the bone is common. Pain usually accompanies a fracture in the 
bird. 
So-called fracture fever may occur in the case of a break of the femur. 
This elevation of temperature may last for a day or two. It is sup¬ 
posed to be due, at least in part, to the absorption of tissue products. 
Process of Repair 
The union of fractures by callus is similar to that which takes place 
in the healing of the wound of the soft parts by first intention. Blood 
is at first extravicated between and around the fragment until the rup¬ 
tured or torn vessels are closed by clot. Within twenty-four hours 
after the injury there begins a simple inflammation from the torn 
vessels of the bone, the periosteum and the surrounding soft parts. 
This process includes an emigration of leucocytes and an exudation of 
fluid. 
Then commences repair. The cells of the osteogenic layer of the 
periosteum begin to proliferate, and to a less extent the same is true 
of the bone corpuscles and surrounding endothelial and connective tissue 
cells. These cells gradually infiltrate, remove the clot, and collect to 
form the temporary callus. From the second day onward, cells 
(phagocytes) are seen containing remains of leucocytes, red blood cor¬ 
puscles, and tissue fragments. In a simple normal fracture there is no 
emigration of leucocytes or pathologic exudation after six days. 
The mass of soft, red, gelatinous granulation tissue is composed of tis¬ 
sue cells, derived from the periosteum, bone, and connective tissue, which 
are similar to the fibroblasts in a wound, with the addition that cells, es¬ 
pecially those from the periosteum, have osteogenic properties, are osteo¬ 
blasts. 7 Between these cells newly formed capillaries grow in from the 
vessels in the haversian canals, periosteum, and neighboring connective 
tissue. The formation of new bone in the callus is like the develop¬ 
ment of bone in membrane. There is, in addition, a variable amount 
of a firm, gelatinous intercellular substance, which when in considerable 
amounts distinctly separates the cells, and gives a bluish appearance to 
the naked eye, and is called cartilage. It appears that when the frac¬ 
tured ends of the bones are kept at rest and in perfect apposition, and 
with a normal rate of callus formation, the process is one entirely of 
formation of bone in membrane, without any preformed cartilage; but, 
on the other hand, if the bones are not in proper apposition movement of 
