LO FISTULA AND POLL-EVIL 
predilection of typical fistula of the withers is 
stubbornly anterior to the summit of the 
withers—in the space where the spines decline 
abruptly into the cervical region. 
The sac forms slowly and without apparent 
pain or discomfort to the patient. We have 
found ample evidence post-mortem in subjects 
that have died from other causes that cysts of 
this character sojourn here without attracting 
attention. ‘They are too small to bulge ex- 
ternally and cause no distress that would at- 
tract one’s attention to them. ‘These hidden 
cysts are sometimes the size of an egg and 
sometimes as large as a base ball, and when 
old are so well encapsulated as to prevent fur- 
ther development. Thus cysts may never de- 
velop into fistule or, in other words, the sac- 
cular stage may never advance into the fis- 
tulous stage. The process is arrested by 
encapsulation and later the fluid content is re- 
absorbed, leaving no trace of its previous ex- 
istence. The resulting cicatrical tissue is lost 
in its connective environment. This process of 
arrested development, encapsulation and reab- 
sorption occurs also in clinical cases. Or in 
other words, a clinical case of fistula of the 
withers in the saccular stage that has never 
been exposed to extraneous microérganisms 
may disappear spontaneously. It is thus that 
