434 
A SINGULAR CASK OF STRINGHALT. 
distributions. The crural and lumbar nerves were perfectly 
healthy. The sciatic nerve, at the aperture through which it 
escapes from the spine, was darker in colour than is usual, being 
of a yellowish brown hue. Its texture was softened, and its 
fibrillae somewhat loosely connected together. The nerve was of 
its usual size; but on tracing it from the ischium, and in its course 
through the muscles of the haunch, several spots of ecchymosis 
here and there presented themselves, and they were more parti¬ 
cularly marked on that part of the nerve which is connected with 
the sacro-sciatic ligament. As the nerve approached the hock, 
it assumed its natural colour and tone; and the fibres given off 
from it to the muscles situated inferior to the stifle-joint were of 
a perfectly healthy character. 
On taking out a portion of the nerve where it appeared to be 
in a diseased state, it was found that this ecchymosis belonged 
to the neurilema surrounding the whole of the internal fibres. It 
was confined to the membranous investiture of the nerve, and the 
substance of the nerve, when pressed from its sheath, presented a 
perfectly natural character. 
The cavity of the cranium, and the whole extent of the spinal 
canal, were next laid open. The brain and spinal marrow were 
deprived of their membranous coverings, and both the thecae and 
their contents diligently examined. There was no lesion in any 
part of them, not even at the lumbar region. 
The articulations of every joint of the hind extremities then 
underwent inspection, and no disease could be detected in either 
of them. 
From the present post-mortem examination, and many others 
which Mr. Spooner had previously instituted, he was of opinion 
that this peculiar affection is not referrible to any diseased state 
of the brain or spinal cord, nor to any local affection of the 
muscles of the limbs, but simply to a morbid affection of the 
sciatic nerve. Other circumstances had more or less varied ; but 
he had not dissected a single case of stringhalt in which he had 
not disease of this nerve—the nerve which mainly contributes to 
supply the hind extremities with sensation and the power of 
voluntary motion. The equal action of the muscles being de¬ 
stroyed in consequence of the diseased state of this nerve, the 
flexors, which are naturally more powerful than the extensors, 
draw the tarsus on the tibia, and the tibia upon the femur, beyond 
the position usually determined by the natural mechanical con¬ 
nexions and movements of these joints; and then, from the pecu¬ 
liar arrangement of the articulating surface, between the tibia 
and the astragalus, the hock-joint suddenly becomes elevated, 
producing that remarkable spasm of the limb which is so marked 
a characteristic of this affection, Y. 
