092 
PROCEEDINGS OF THE 
was in contact with the infectious pus that had escaped from the 
vomica. 
Inflammation of the arachnoid membrane of the brain has been 
observed in several horses. Phlebitis has been almost always 
the cause of this. Post-mortem examination of some of these 
horses proved that inflammation of the arachnoid membrane 
takes on the same morbid characters as that of the pleural serous 
one, and that the symptoms which are termed vertiginous are 
rarely observed in this inflammation, and of which they would 
not be at the time a decisive symptom. 
In his anatomical researches into the spinal cord of the horse, 
M. Renault has been accustomed to direct the attention of the 
student to a canal in the centre of the cord, and which may be 
traced, with a little care, from the calamus scriptorius to the ter- 
mination of the lumbar portion of the marrow. This canal, most 
apparent when examined near to the head, is always filled with a 
serous fluid, which exudes in minute drops when the spinal cord 
is pressed upon after an incision has been made through it. 
It results from the existence of this canal in the horse (the 
animal to which alone the researches of the professor have ex- 
tended for this especial purpose), that the cerebro-spinal nervous 
centre is bathed exteriorly and interiorly by two distinct fluids. 
The one inclosed in the meshes of the pia-mater, under the arach- 
noid membrane, is that which is called the cephalo rachidian , or, 
more properly, the sub-arachnoidean fluid. The other, filling 
the ventricular cavities of the cerebrum and the cerebellum, and 
also that in the canal of the spinal marrow, should be distin- 
guished by the name of the ventricular fluid. There is one 
peculiarity which, perhaps, is not without importance, — that the 
sub-arachnoidean fluid, very abundant around the spinal marrow, 
is found in an exceedingly small quantity around the cere- 
brum and cerebellum, while the ventricular fluid, the quantity of 
which is very considerable in the cavities of the brain, is per- 
ceived only in the form of exceedingly small drops in the central 
canal of the spinal marrow. 
On opening a gland ered horse, that died in consequence of a 
wound penetrating into the chest, a remarkable lesion of the 
heart was discovered. The right auricle, the volume of which 
was very much increased, weighed two pounds. It was thick- 
ened and ossified through nine-tenths of its extent. The fleshy 
fibres which naturally entered into the structure were com- 
pressed and atrophied by the ossiform concretions that were 
formed in the cellular interfascicular tissue. On the convex sur- 
face of the auricle the ossification presented the hardness and 
the resonance of bone. It was less advanced in the interior 
