THE EYE 405 
and capillaries producing marked general or nodular thickening in 
some places. Accompanying these hj^jerplastic changes there was a 
marked calcification of some of the arteries. This was not confined 
to one tunic, but in some instances it extended almost completely through 
the vessel wall, and here and there the lumen of a vessel was nearly 
obliterated. The main features were endothelial hyperplasia, edema of 
the pia and of the subpial cortex with some calcification of the vessels. 
It was perhaps less well marked in the occipital lobes than in other 
parts. The optic nerve and other portions of the brain appeared to 
be normal. 
Moon Blindness. 
It seems also profitable to repeat here a report Dr. H. 
M. Langdon and I made in 1911 upon a horse with periodic 
ophthalmia or ''moon blindness," a widespread condi- 
tion and one upon wliich there is even to-day little known 
and much contradictory theorizing. It is worthy of 
record that Dr. J. H. W. Eyre of Guy's Hospital, had a 
case to study at the same time as ours. He did not find 
the protozoon-like body discussed below, but laid weight 
upon the isolation of St. aureus, an organism often men- 
tioned in the literature about this disease. I cite the 
whole report since our publication in the 1911 Report of 
this Garden seems not to have been quoted in any of the 
reference articles on "Moon blindness." Those who are 
interested in the clinical and pathological sides of the 
question will find a good summary in Veroff. aus der- 
Jahres. Vet. Berichten der heamt. Tierdrzte Preussens, 
1908, and the bacteriology of the equine eye by Karsten, 
Inaug. Disser. Giessen, 1909. 
''During the latter part of 1909 and first part of 1910 
we had a horse referred to us suffering with recurrent 
ophthalmia or moon blindness. This affection, suggested 
by its name, is supposed to have some relation to the lunar 
periods. Some points in our work showed that such may 
be the case. Attacks appear not infrequently at the time 
of the full moon, and in our only experimental infection 
twenty-eight days elapsed between inoculation and a 
general ocular inflammation. 
