12 
The Bulletin 
of one-half cut out and placed in 10 per cent hydrochloric acid solution 
for forty-eight hours for decalcification, and then passed through three 
changes of absolute alcohol, and then through equal parts of alcohol 
and ether, then imbedded in liistoloid and sectioned. The sections were 
stained in hematoxylon and eosin and clarified in oil of cedar and 
mounted in natural balsam for study. Figure 2, letter A, shows a sec¬ 
tioned surface of a metatarsus of a Single-Combed Rhode Island Bed 
cockerel eight days after the fracture. There was a mottled reddish 
white zone in the region of the fracture, indicating that immediately 
following the fracture there was an extravasation of blood which had 
collected around and between the fragments and between the ends of 
the compact portion of the bone, and had also invaded, to a certain 
extent, the marrow cavity. The fluid at this time gave some evidence 
of advanced organization and was rather callus-like, hut allowing the 
fractured ends of the hone to separate when traction was applied. 
There was present the initial hyperemia of repair. This hyperemia 
was most marked in the periosteum. Leucocytes, whose function it is 
to digest and remove the detritus resulting from the injury, had invaded 
the parts. Proliferated changes had taken place in the connective 
tissue, and in fact this was observed in cases of only forty-eight hours 
standing. The most active cellular multiplication was in connection 
with the fibrous structure of the periosteum. This forms the germina- 
tive or reparative tissue from which arises the osteoblasts. The nature 
of the new formed structure was that of connective tissue, and in Fig¬ 
ure 4 may be seen the commencement of this organization into trabecu¬ 
lar-like arrangement forming the periosteal callus and the provisional 
plug. It can be seen that this has been poured out and formed from 
the periosteum. This field shows many fibroblasts and is packed with 
osteoblasts and osteoclasts, and in still other fields of the trabeculae a 
homogeneous matrix with formative bone cells in their lacunae. The 
repair is apparently one of intramembranous bone formation, with 
islands of new formed bone at the end of the fifth day. 
In Figure 2, Letter B, is seen a sectioned surface of a fractured meta¬ 
tarsus of thirteen days standing. This bone is from a one-year-old 
Single-Comb White Leghorn hen, who was of low vitality and the re¬ 
parative processes were more tardy than in section, letter C, shown in 
the same cut. After the metatarsus was removed it could with con¬ 
siderable force be made to spring, which was not the case in C, where 
the same amount of force was used. Both birds showed the reparative 
processes far enough advanced to have the appliance or cast removed 
with safety. 
From these two studies it is rather indicative that repair of the bone 
of the domestic fowl is quite rapid and that twelve days is ample time 
to allow the bandage or cast to remain in place. 
