490 NORTH OF ENGLAND VETERINARY MEDICAL ASSOCIATION. 
the objects in which—except in certain particulars hereafter 
to be noticed—were observed to be in a normal condition. 
The lateral ventricle of the left hemisphere was exposed in 
a similar manner, when a mass of disease presented itself. 
The cavity was filled with a thick matter not unlike curds in 
consistence, semi-transparent, and of a blue-gray colour in 
places, varying to an opaque, with shades of dark pigment 
increasing to blackness, especially when viewed in the mass. 
The medullary matter forming the roof of the natural 
cavity was implicated, being softened and broken down, and, 
in the centre, absolutely wanting. 
The cortical portion was inky in appearance, and stained 
the fingers. The space, being the part in area affected, nearly 
corresponded to the size of the ventricle above, and was at the 
central point not a quarter of an inch in thickness. 
The only recognisable object contained in the left ventricle 
was the choroid plexus, which was considerably enlarged, 
congested, and lying, as it were, in a fissure or depression, 
between two eminences of the opaque matter referred to. At 
its origin within the ventricle, at the posterior or superior 
cornu, it was covered, and, where it passes through the fora¬ 
men communis inferior in the healthy subject in the present 
instance, possessed an unusually strong attachment to some 
object occupying a position in the mesian line. Here it was 
surrounded by a cloudy mass of the same kind of matter, 
which was connected to, or continuous with that which occu¬ 
pied the space of the left ventricle, extending from the pillars 
of the fornix posteriorly or superiorly, anteriorly, or interiorly 
to the genu of the corpus callosum, and laterally within the 
right hemisphere and ventricle to the inferior cornu and base of 
the corpus striatum; all of which , with the fifth ventricle and 
septum lucidum, were obliterated. 
The greater portion of matter being removed from the 
surface of attachment of the choroid plexus, an irregular 
ovoid mass presented itself, about the size of a pigeon's egg, 
imbedded in the elastic mass with which it was surrounded, 
as if in the process of accumulation. It was raised from its 
position by the forceps, drawing with it a considerable 
amount of matter and, being deprived of this it had all the 
physical characters of a cartilaginous tumour. In length it 
was about an inch, and in breadth about five eighths; the long 
axis being across the mesian line, and greater portion within 
the left ventricle. 
I have endeavoured to illustrate this interesting subject 
by means of drawings made from a horizontal and vertical 
section of the lobes. 
Here I would inquire, As blindness gradually succeeded 
