240 
TREATMENT OF SADDLE-GALLS. 
pressure should be maintained by means of antiseptic dressings to prevent 
recurrence. Particular care is required in using the knife, and fluctuating 
swellings must only be opened when it is quite clear that pus exists. It 
is preferable, in doubtful cases, to employ a blister of cantbarides, 
sublimate, or biniodide of mercury, by which a swelling is caused and 
moderate pressure produced on the extravasated material, bringing 
about resorption. 
Pus formation in the region of the withers renders treatment very 
difficult. Pemoval of pus and necrotic material, and prevention of fresh 
pus formation and necrosis are the chief objects to be sought in these 
cases. The knife must often be used freely. Fistulae should, if possible, 
be laid open to their extremity, pockets exposed, and necrotic pieces of 
lig. nuchse, of fascia and of superior spinous processes removed as soon as 
possible. Setons and drainage-tubes assist the escape of the discharge, 
and prevent fresh burrowing of matter. In the event of pus forming 
beneath the muscles, these are laid open, but care must be taken not to 
divide the skin crosswise over the middle line of the back, because in 
this way wounds result, which heal with difficulty on account of their 
edges turning inwards. Sometimes suppuration extends to the muscular 
tissue of the neck, which must then be laid open, usually as deeply as 
the lig. nuchse, which, as in poll-evil, requires to be divided. Necrosis 
of the ligament itself necessitates free removal of the affected parts. In 
such exceptional cases Hertwig and many others recommend dividing the 
ligament an inch or two in front of the necrotic portion (desmotomie 
cervicale). A mass of new tissue forms at this point, constituting a 
barrier to the further spread of necrosis. Once this is produced the 
fistula is freely laid open, and all the necrotic portions of the ligament 
behind the cicatricial tissue removed. 
The greatest difficulty is experienced where necrosis has attacked 
the superior spinous processes of the vertebrae. Separation takes a 
long time, and during this process new pockets may form and fresh 
structures become necrotic. Should the diseased parts be removed with 
the curette or saw, fresh necrosis usually occurs on the surface of the 
bones, so that with this operation no progress is made. Removal of 
the diseased spinous process is only successful where permanent irriga¬ 
tion can be provided for, and perfect asepsis attained ; but, in such 
cases, the results are often astonishingly successful. Unfortunately 
the inflammation and pus formation only occasionally allow of this. 
Good recoveries can only be expected where pus formation has almost 
entirely disappeared, and where no marked swelling exists. 
Cadiot and Dollar describe a case of fistulous withers complicated with 
necrosis of the supra-spinous ligament, and at a later stage with necrosis of 
the ligamentous tissue covering the sides of the superior spinous process of 
