68 FISTULA AND POLL-EVIL 
It does not matter whether the condition has 
been caused by an abrasion or has originated in 
a cyst of the dorsal bursa, procrastination is 
inadvisable. 
We have found, however, in the cases of typi- 
cal fistulae that the evacuation of the contents 
of the sac one week before the radical operation 
is performed, is good practice, because it forti- 
fies the tissues against post-operative infections 
of a grave character. Where strict aseptic con- 
ditions are maintained in the operation and 
the patient has skillful after-care, this precau- 
tion is not as essential as when careless methods 
prevail or when the after-care must be con- 
signed to untrained hands. 
It is, therefore, recommended, as a routine 
measure in field practice, to lance the cyst, 
evacuate the liquid and floceulent contents and 
then submit the sac to casual irrigations one 
week to ten days before operating. 
In the case .of old fistule originating as 
cysts and which have become infected from 
any source or in the traumatic variety having 
either superficial or deep pus accumulations, 
lancing one week before operating is likewise 
helpful in that surgical shock is modified and 
there is less soiling of the surgical wound with 
pus durmg the operation. 
These suggestions need not be laid down as 
