88 FISTULA AND POLL-EVIL 



be watched more carefully. They must not be 

 allowed to close above before sequestration is 

 complete and the bone is in condition to cica- 

 trize with the rest of the wound. It is here 

 that recurrences occur. Stumps of bare verte- 

 brjE are covered by scar tissvie and cause a re- 

 accumulation of pus which will require subse- 

 quent attention if not a second operation of 

 equal magnitude. 



During the healing of the wound its walls 

 are scrutinized daily for shreds of ligament 

 that are becoming surrounded with granula- 

 tions before detaching from their viable con- 

 tinuation. It often happens that large sloughs 

 of ligamentous or new-formed fibrous tissue 

 appear here and there about the cavity as cica- 

 trization proceeds. These delay healing and 

 should be removed as soon as possible. 



At the end of five weeks we usually dispense 

 with the tube and apply such simple astring- 

 ents as a two per cent solution of zinc sul- 

 phate or common white lotion. At this time 

 horses may be worked with breast harness 

 but collar pressure directly upon the region is 

 not admissible until after three months have 

 elapsed. 



Modifications 



Large subcutaneous or subfascial abscesses 

 are evacuated at dependent points and drain- 



