130 
DEPARTMENT OF SURGERY. 
cysts are unbroken it is impossible to determine the condition 
that causes the disturbance observed, but when they rupture 
into the pleural cavity a puncture made tentatively, with a 
history of the case, may give rise to a chain of evidence that 
will lead to some definite conclusion. 
KERATOCENTESIS. 
There are certain conditions of the eye which can be suc¬ 
cessfully treated by tapping the anterior chamber, either to 
remove injurious bodies or material contained therein, or to 
reduce the pressure upon the cornea or walls of the anterior and 
posterior chamber of the eye. The removal of the aqueous 
humor is often followed with very good results, such as stimu¬ 
lating the functional activity of its secreting membrane ( Dese - 
met's membrane) ; encouraging the absorption of substances 
which cause opacity, haziness, cloudiness or loss of transparency 
of the cornea and anterior surface of the lens ; and also prevent¬ 
ing absorption of the cornea, which is always followed by escape 
of humors and complete destruction of sight. 
Keratocentesis has its indications and contra-indications, 
e. g ., it can be used to a good advantage in aplastic iritis, but 
FIG. 45- 
METHOD OF EXAMINING THE EYE. 
