496 VETERINARY SURGICAL OPERATIONS 



drainage tube, which is then passed through the cavity and 

 fastened at the superior orifice to prevent it from slipping, 

 downward. The whole surface is then coated with collo- 

 dion. 



The after-care consists of probing the tube to prevent 

 blocking up with dried secretions, feeble irrigations of perox- 

 ide of hydrogen administered through the tube, and re- 

 moval of the sutures when the proper time has arrived. 



A dose of antitetanic serum should always be adminis- 

 tered to valuable charges, as such wounds are decidedly tet- 

 anogenic, whether treated as open or closed. 



Subperiosteal Fractures. 



. Fractures without immediate displacement occur with 

 considerable frequency in horses, generally from kicks of 

 other horses. The points of predilection of these injuries 

 are (i) the internal surface of the tibia, especially the middle 

 and inferior thirds; (2) the inferior third of the anterior 

 surface of the radius, "just above the knee," and (3) the su- 

 perior third of the external border of the radius "just below 

 the elbow." At these three points the bones are exposed 

 with no protecting envelope except the skin, and the perios- 

 teum is so thick and of such unusual toughness that a wicked 

 kick may shatter the underlying bone without causing an 

 immediate displacement. The fracture may be complete or 

 partial, transverse or oblique, simple or comminuted, and 

 yet produce no immediate lameness or indisposition to har- 

 monize with the seriousness of the injury. A horse so in- 

 jured will sometimes walk for several miles or even perform 

 an ordinary day's work before any pronounced lameness de- 

 velops, and then after several days of rest the lameness may 

 disappear, leaving the patient apparently ready for service 

 again. Dependent upon the character of the fracture, ten to 

 twenty days may elapse before the segments separate, and 

 for the first time reveal the nature of the injury by a sudden 

 dangling of the leg, crepitation and inability to support 

 weight. Moller mentions a case in which one hundred and 

 twenty-seven days elapsed between the date of injury and 

 the date of separation. Hughes reports several cases in which 

 the final dissolution of the bone occurred from three to four 

 weeks after the accident, and the author observed the follow- 

 ing interesting circumstace : A trotting stud twelve years 

 old was kicked in the lower third of the radius by a mare 

 about to be served. There was but a slight abrasion of the 

 skin, and although he limped conspicuously after the acci- 



