PATHOGENESIS 49 
viding there are no secondary cavities that do 
not drain. 
During the fistulous stage of the disease we 
must reckon, therefore, with a slowly dying 
ligament, exfoliation of the ends of the spines, 
the secondary pus due to the burrowing of pus 
into adjacent spaces and the fibrosis that con- 
tinues to encroach upon the surrounding mus- 
culature. It is plain that these constitute a 
combination of very inimical conditions. There 
is also in addition to these, a chronic septicemia 
that slowly but surely undermines the general 
health and manifestly reduces the patient’s 
vitality. The tracts leading from pus cavities 
to the surface apertures, to still further com- 
plicate matters, close up by cicatrization from 
time to time and thus pen up the pus again until] 
it has burrowed out a new channel. During 
this occurrence the patient is again sick as in 
the phlegmonous stage, exhibiting pain, dis- 
tress in movement, fever and general malaise. 
Each attack of this kind leaves the patient more 
enfeebled and still further damages the withers 
by forming new tracts, more fibrous tissue and 
sometimes new secondary cavities. The disease 
ends in one of two ways: the common one is 
emaciation and death, and the other is chronic 
fistula, discharging limited amounts of pus for 
several years. Rare cases heal up spontan- 
