CHOROID PLEXUSES OF THE HORSE. 145 
On cutting into the body of the lateral ventricles, a tumour 
was seen on the anterior part of either choroid plexus. No other 
trace of disease was detected in any part of the encephalon; it 
was, however, unusually vascular. 
The right tumour was two-thirds of an inch in length, by 
half an inch in breadth. It was composed of a large and two 
smaller masses, resembling fat, apparently enclosed in a thin 
capsule, and appended to the under and anterior part of the 
choroid plexus. 
The left enlargement measured two-thirds of an inch antero- 
posteriorly, by five lines in breadth. It had a vesicular appear¬ 
ance supero-anteriorly, whilst at the posterior and upper part 
was a lump similar to those described in the right one. 
This appearance suggested that it might probably be some 
degeneration of materials which had been effused beneath the 
lining membrane of the choroid plexuses, and interstitially 
within the villi at the upper part of the left one. I have never 
before seen tumours of the like kind so distinct and circum¬ 
scribed ; in other instances they have appeared to me to be more 
especially due to interstitial deposit, whilst here the substance 
most probably existed between the serous and fibrous layers 
contributing to form the choroid plexuses. 
Microscopic Examination. —The contents of the enlarged 
villi consisted of crystals of cholesterin granular matter, which 
was partly soluble in ether, and partially not so, proving that it 
was not altogether fatty. There were also some blood discs, 
not unlikely escaped from the bloodvessels divided in cutting 
through the villi, and epithelial scales modified in shape. 
The more distinct tumours contained a pulpy substance of a 
yellowish white colour, composed principally of crystals of choles¬ 
terin with globular bodies, varying in size from - 4^0 to of 
an inch in diameter, closely resembling oleine, inasmuch as they 
were gradually shaded from circumference to centre, and 
appeared devoid of structure. 
Fig. 1. 
On adding hydrochloric acid, these apparently characteristic 
globules of fat dissolved without effervescence, whilst ether did 
