512 
ARTIFICIAL PRODUCTION OF BONE. 
the remainder of the periosteum being still fibrous. The 
new bone adheres to the old bone whence the periosteum has 
been borrowed, and that by so considerable a base as to give it 
the appearance of an apophysis, b. The communicating pedicle of 
the flap is excised three or four days after the transplantation, so 
as to cut off all communication with the bone. The ossifiable 
exudation continues none the less, and new bone is produced, 
which is adherent or moveable accordingly as the strip is re¬ 
applied to the bone or left quite independent, c. The flap is com¬ 
pletely divided at the time of the operation,and transplanted amidst 
neighbouring or distant parts. Thus, the strips have been 
transplanted under the skin of the groin, the back, &c., or 
placed in the midst of the crest of a cock; and in all 
instances ossifiable secretion has resulted—the osseous pro¬ 
duction being large in proportion to the size of the animal 
and the extent of the periosteal strip. Bones from one to three 
centimetres in length, and of varied form, have been produced. 
The nature of the medium in which the transplantation was 
effected influenced the result; and the crest of the cock, owing 
to its rich vascularity, constituted an excellent soil for this 
• • * 
artificial osteogenesis. 
(2.) Transplantation of the periosteum of one animal to another 
of the same or of a different species .—These interchanges have 
been tried between the dog and the rabbit, the rabbit and 
the guinea pig, the fowl and the rabbit, and the dog and the 
fowl. Periosteum transplanted under these circumstances 
may comport itself in different ways : a . Occasionally it may 
become absorbed soon after the transplantation; b. it may 
become gangrenous, and be discharged by suppuration—and 
this was almost constantly the case at Paris with respect to 
rabbits, in which the periosteum of the dog had been applied ; 
c. the flap may remain encysted without giving rise to 
suppuration ; the cysts after a while being found to contain 
only fatty matter or concrete pus ; d. the periosteum adheres 
to the surrounding tissues, and is penetrated with new 
vessels, but it has lost its osteogenic properties, and con¬ 
tinues only as a vascular and fibrous membrane; e. the 
periosteum not only contracts fibrous and vascular adhesions, 
but produces osseous tissue. This is brought about with 
much more difficulty than in the case of transplantation in 
the same species, depending upon conditions which require 
to be more accurately ascertained. 
(3.) External appearance and structure of the bone produced 
by transjilanation .—The bone thus produced is not a mere 
calcareous concretion, or even an unformed mass of osseous 
substance. Its texture presents a disposition analogous to 
