478 VETERINARY SURGICAL OPERATIONS 



and especially general symptoms, — fever, anorexia, _accel- 

 erated respirations, etc., — indicate invasion of the navicular 

 bursa. The suspicion is at once confirmed when the wound 

 begins to discharge a thin, watery liquid-synovia that co- 

 agulates upon the dressing. This complication may require 

 more radical intervention. See page 461. 



It is also always advisable to administer an immunizing 

 dose of antitetanic serum. 



Nail-Treads. 



Nail-treads is the name we apply to pricks from one or 

 more nails caused by treacling upon a shoe partially 

 wrenched fromi the foot. The nails of a loose, clacking, 

 badly worn shoe, drawn from their tracts with the shoe 

 about to be cast off, are sometimes trampled into the foot 

 along the solar margin, but the most common cause of the 

 accident is the forcible wrenching of a shoe whose toe-calk 

 or heel-calk becomes fixed into a crevice in the street pave- 

 ment, railroad switches, defective street-car tracks, draw- 

 bridge, etc. While these menaces may thus cause the shoe, 

 and sometimes the whole hoof, to be torn off completely, 

 more often the shoe is only wrenched from one side of the 

 foot and the protruding nails whose heads are still tightly 

 wedged in their sockets, penetrate the sole at the next step. 

 This form of penetrant nail presents entirely different phases 

 from the typical "picked up" street nail. The latter usu- 

 ally invades the region of the. frog, and complicates matters 

 by implicating the navicular synovial bursa, while the form- 

 er invades the border of the sole, and when serious involves 

 the affected zone in an acute osteitis and laminitis that end 

 in a more or less extensive necrosis of the os pedis and 

 laminse, and not infrequently in quittor. 



PREVENTIVE TREATMENT.— The fact that it is 

 usually the toe-calk that becomes caught in the defective 

 street suggests the advisability of so shaping this part of the 

 shoe as to reduce these accidents to the minimum. This 

 may be done by making the toe-calk curve to the contour 

 of the shoe instead of extending straight across the toe. The 

 curved calk, three to four inches long according to the size 

 of the shoe, seldom' ever catches in street crevices. At the 

 heels adequate protection is found in rubber pads. 



TREATMENT.— The "first aid" treatment does not 

 differ from that of the street nail. Paring the hoof thin 



