802 BUREAU OF ANIMAL INDUSTRY. 



consolidated, or united; in the second there is u false articulation, or 

 2)scudarthrosls. 



The time required for a firm union or true consolidation of a frac- 

 ture will vary with the character of the bone affected, the age and 

 constitution of the patient, and the general conditions of the case. 

 The union will be perfected earlier in a 3'oung than in an adult ani- 

 nnil, and sooner in the latter than in the aged, and a general healthy 

 condition is, of course, in every respect, an advantage. 



The mode of cicatrization, or method of repair in lesions of the 

 bones, has been a subject of much study among investigators in 

 I)athology, and has elicited various expressions of opinion from those 

 high in authority. But the weight of evidence and preponderance of 

 opinion are about settled in favor of the theory that the law of repa- 

 ration is the same for both the hard and the soft tissues. In one case 

 a simple exudation of material, with the proper organization of newly 

 formed tissue, will bring about a union by the first intention, and in 

 another the work will be accompanied by suppuration, or union by the 

 second intention, a process so familiar in the impair of the soft struc- 

 tures bv^ gi'anulation. 



Considering the process in its simplest form, in a case in which it 

 advances without interruption or complication to a favorable result it 

 ma}^ probabh' be correctly described in this wise: 



On the occurrence of the injury an effusion of blood takes place be- 

 tween the ends of the bone. The coagulation of the fluid soon fol- 

 lows, and this, after a few days, undergoes absorption. There is then 

 an excess of inflammation in the surrounding structure, which soon 

 spreads to the bony tissue, when a true ostitis is established, and the 

 compact tissue of the bone becomes tlie seat of a new vascular organi- 

 zation, and of a certain exudation of plastic h^mph, appearing between 

 the periosteum and the external surface of the bone, as well as on the 

 inner side of the medullary cavitj'. After a few da3's the ends of 

 the bono thus surrounded by this exudate become involved in it, and 

 the h'mph, becoming vascular, is soon transformed into cartilaginous, 

 and in due time into bony tissue. 



Thus the time required for the consolidation of the fractured seg- 

 ments is divisible into two distinct periods. In the first they are sur- 

 rounded by an external bony ring, and the medullary cavity is closed 

 by a bon}' plug or stopper, constituting the period of iha provisional 

 callus. This is followed by the period of vermancnt callus, during 

 which the process is going forward of converting the cartilaginous into 

 the osseous form. 



The restorative process is sooner completed in the carnivorous than 

 in the her])ivorous tribes. In the former the temporary- callus may 

 attain sufiiwent lineness of consistency^ for the careful use of the limb 

 within four weeks, but with the latter a period of from six weeks to 



