OSTEOMALACIA—OSTEOCLASTIA—OSTEOPOROSIS. 487 
‘bent ; however, it frequently happens that after a certain time, by regular 
exercise and good diet, the deviations of the bones disappear almost com- 
pletely. As soon as the bony nutrition is reéstablished, at both extrem- 
ities of the bent diaphysis, the bone grows straight, the periostic ap- 
‘positions take place most exclusively in the concavity of the diaphysis, to 
“such an extent that after complete development, the bone has a normal 
-shape. 
When, on the contrary, a deformity remains upon one of the bones of 
‘the extremities, there is no hope to straighten it except by osteoclasia or 
-osteotomy ; operations which will never enter in our surgery. What is 
‘difficult, is not to break up the bone—the osteoclasts of Colin and Robin 
-answer that purpose (osteoclasia),—or to divide it with shears after inci- 
‘sion of the skin (osteotomy) ; but to keep them in good position. Our 
‘patients are restless, they constantly move and displace their dressings ; 
‘the regular union of the separated ends would be uncertain. Therefore, 
‘with them, the treatment of rachitism is almost exclusively medical. 
Rachitism is not very rare in birds kept in captivity or domesticity (Lar- 
“cher, Mégnin.) It is observed specially in chickens, pheasants, turkeys, 
‘pigeons, ducks, geese and blackbirds. It appears ordinarily in the first 
‘months of life. Sometimes all the bones are affected, at others it is 
dimited to a few, habitually to the bones of the trunk (vertebra, ribs, 
sternum, pelvis.) Life outside, strengthening diet, stimulating frictions of 
the legs (alcohol, hot wine), such is the treatment to follow. 
IX. 
OSTEOMALACIA—OSTEOCLASTIA—OSTEOPOROSIS. 
Some authors describe in special chapters osteomalacia, osteoclasha 
cand osteoporosis. Osteomalacia, seen in horses, dogs, and goats, is 
characterized, as we have said, by the softening of bones in adult sub- 
jects. In osteoclastia, special to bovines, there is no softening, no de- 
formation of bones ; the spongy substance is partly resorbed and the med- 
cullary canal increased. Osteoporosis consists specially in a dilatation of 
the Haversian canals with resorption of the compact bony substance. 
‘Germain has observed this affection upon our horses in Cochinchina, with 
-an enzootic character. Most pathologists, with Friedberger and Fréhner, 
make no difference in those affections; they consider them only as mor- 
‘bid forms having causes of similar order, from which at last results an abnor- 
mal fragility of the bony tissue, due to the resorption of its spongy, of its 
compact substance or of its calcareous salts. This fragility is principally 
observed in bovines (cachexia ossifraga.) 
The disease begins either by rheumatismal pains or by synovitis: these 
