ph spaces
and Schlemm's canal by cicatrical contraction, as in sclero-keratitis.

2. Those that cause obstruction to the lymph spaces at the filtration
angle by the deposition of fibrin or cellular elements, as in iritis,
hemorrhage into the anterior chamber, etc.

3. Those that cause obstruction of the filtration angle by advancement
of the iris and lens, as occurs when the volume of the contents of the
vitreous chamber is increased, as from retinal or chorioidal hemorrhage
or neoplasm.

The various changes are so numerous that they need not be described
further here. The ultimate changes due to high tension resemble those
already described.

Dr. John E. Weeks' Paper on Pathology of Glaucoma

Discussion,

E. V. L. BROWN, M.D.,

Chicago.

I would like to emphasize one of the newer features of the pathologic
anatomy of glaucoma, one which has received too little attention in this
country: the _lacunar_ or _cavernous atrophy_ of the _optic nerve_.

The name accurately describes the condition. Tiny clear spaces form in
the lamina cribrosa and in front and behind it in the nerve tissue.
Their exact nature is unknown. Usually they are entirely empty, often
they are traversed by fine glial fibers. They seem to be in no relation
to the blood vessels. Adjoining lacunae are supposed to fuse to form
larger cavernae and these finally merge and constitute the final
glaucoma cup. The lamina may then bridge across the space like a cord,
or lie back against the end of the nerve trunk.

Schnabel considered all glaucoma cups to be formed in this way,
independent of tension. His views were strongly supported by Elschnig,
but as vigorously opposed by others. Axenfeld cites the fact that the
glaucoma cup may disappear after operation. (I myself have seen a cup of
7 D. reduced to 1 D. in the course of a year after the tension had been
lowered from 62 to 12.) Stock found the same lacunae in eight cases of
myopia. The last extended study of the subject was made by E. v. Hippel,
who found lacunae in 20 of 33 cases (60 per cent); enough certainly to
make one look for them carefully in every case. He publishes a large
number of excellent photo-micrographs, but none more typical than one I
have in my possession.

I have been especially interested in this subject because I have met
with a complete and total glaucoma cup, with the typical (ampulliform)
undermining of the scleral ring, in a pair of eyes without increased
tensi