-ocular tension is correct, that they are
able to relieve the pain of primary and of secondary glaucoma would
seem to be proved by many observations, some of which I have myself
made, and other very accurate and excellent ones have been made by
Risley in Philadelphia.

A word might be said in regard to _diathermy_. According to Zahn, the
method of applying diathermy to the human eye is to take a layer of
cotton wool 1 cm. thick soaked in a 2 per cent solution of sodium
chlorid, which is applied close to the outside of the lids. On this is
put an electrode 15 cm. in size with a large indifferent electrode
applied to the back of the neck. It is not germane to the subject to
name the various ocular diseases which were treated in this manner, but
Clausnizer has made an investigation of the influence of diathermy on
intra-ocular tension. In a number of diseases, for example,
iridocyclitis, the method produced distinct rise of pressure. In one, a
patient with secondary glaucoma, prior to the diathermic application
the tension was 371/2 mm., after the passage of the current it had
fallen to 28 mm., but the next morning the tension rose to 45 mm. In a
patient with chronic glaucoma no definite alteration of tension could be
found. This observation is mentioned, not because it puts us in
possession of a valuable therapeutic measure, but largely because it is
a good example of how in this disease it is wise to investigate any
method which furnishes a hope of relief.

In a few instances endeavor has been made to reduce the intra-ocular
tension, or at least to relieve glaucomatous symptoms, by galvanism of
the cervical sympathetic, for example, by placing one electrode along
the whole length of this nerve in the neck and one on the back of the
neck on the opposite side, 15 to 20 ma. of current being used. Good
results have been reported by an observer named Allard. I confess that I
am entirely faithless in regard to any results that may be reached in
this manner. It is possible that as the positive pole is a sedative, if
there were any influence, the influence of sedation would be present,
but certainly it has over and over again been experimentally proved that
irritation of the cervical sympathetic quite rapidly produces elevation
of intra-ocular tension of 2 to 4 mm. In some experimental work the
primary elevation of intra-ocular tension was followed by a secondary
drop.

3. _Indirect reduction of increased intra-ocular tension