NERVOUS SYSTEM. (Nervous Cenrres. Apnnormat Anatomy.) 
the spinal canal. The softening which results 
from decomposition, in general, occupies the 
greatest part of the cord or the whole of it, and 
~ does not exhibit so pure a white colour as the 
morbid softening. It sometimes has a greenish 
or a dusky hue, and is more or less fetid. 
The softening from injury is very circumscribed, 
and is surrounded by nervous matter perfectly 
healthy in colour and consistence. There is, 
moreover, generally evidence of injury to and 
rupture of the pia mater, the softened matter of 
the cord protruding through the rent in this 
membrane. Where the softening is morbid, 
it wants the abruptness which occurs in the 
latter case, and the diseased part gradually 
passes into healthy structure. 
The inflammatory softening is sometimes 
infiltrated with purulent matter, which, if not 
recognizable by the naked eye, may be easily 
detected by the microscope and by reagents. 
In rare cases the pus is collected into a circum- 
_ Seribed abscess, occupying more or less of the 
__ thickness of the cord. 
___ The cord may be the seat of an effusion of 
blood, and may thus present the condition of 
_ apoplexy, like that which is of so frequent 
_ occurrence in the brain. In such cases there 
may be more than one small clot occupying 
the central part of the cord. They are of 
are occurrence, and are generally found in 
_ the upper part of the cord. 
Tubercle may occur in the cord, and, as in 
_ the brain, connected with the pia mater, either 
deposited in a group or forming a mass which 
_ gradually encroaches upon the substance. The 
| cervical region is that in which it most fre- 
| quently is found, and it forms tumours of va- 
ious sizes, each of which is generally enclosed 
in membranous cyst. 
_ Cancer of the cord is a lesion of extremely 
_ ¥are occurrence. Olivier relates several cases 
of it, but Rokitansky remarks that he has seen 
_ but one example of a cancerous tumour in the 
Spinal cord. It is in cases where the cancerous 
liathesis prevails, and where cancerous matter 
‘is deposited throughout various parts of the 
_ body, that we may look for it in the cord. 
_ Abnormal anatomy of the brain and its mem- 
—The remarks already made with re- 
to the membranes of the cord apply 
kan to those of the brain. The latter mem- 
d » however, are more frequently found in 
abnormal state than the former. 
_ The dura mater—There may be a general 
or partial deficiency of the dura mater and of 
t membranes according as there is a 
general or partial defect in the brain itself. 
_ The partial defect is mostly observed in the 
falx cerebri or in the tentorium cerebelli. The 
| cribriform appearance of the former process is 
of frequent occurrence and is unaccompanied 
by any obvious defect in the brain, and some- 
times even a considerable portion of it is want- 
| ing, while the brain is quite normal. 
Acute disease of the dura mater is rare, and 
only occurs as an effect of wounds or injuries 
_ | of the cranium, or in connection with syphilitic 
. er strumous disease of the bones; or, inde- 
\pendently of diseased bone, as an effect of the 
715 
syphilitic poison, like that which occurs on ex- 
ternal fibrous membranes, A syphilitic in- 
flammatory state of the dura mater is frequently 
the cause of serious affection of the brain. A 
condition analogous to that of node will cause 
pressure on the brain and paralysis; and, 
whilst it resists the ordinary antiphlogistic 
treatment, will speedily yield to antisyphilitic re- 
medies, such as mercury and iodide of potassium. 
We meet with great variety as regards the 
firmness of adhesion of the dura mater with 
the cranium. There is a tendency in some 
perverted states of nutrition for this membrane 
to become incorporated with the inner table of 
the skull. This seldom takes place conti- 
nuously, but in patches, so that in removing the 
calvaria a portion of the inner table of the skull 
remains in connection with the fibrous mem- 
brane, or a hole is left in the latter when the 
conversion of the fibrous membrane into 
bone may be complete. It is in the 
more advanced periods of life that this mor- 
bid condition is chiefly found; indeed we 
seldom open the skull of a person who has 
passed the age of threescore without finding 
more or less of it. At that period of life it 
may be regarded rather as one of the series of 
changes which accompany advancing years 
than as a diseased state. When, however, it 
occurs at the earlier ages, it must be viewed as 
resulting from a morbid process. 
Patches of bone are frequently found in the 
processes of the cranial dura mater, as in the 
falx, tentorium. They occur more frequently 
in the former than in the latter. In size they 
vary much: they are placed between the layers 
of the dura mater, and are completely enclosed 
by them; sometimes, however, they encroach 
upon these layers, which then seem as if they 
had been completely converted into bone. 
Fibrous tumours are sometimes formed at 
various parts of the dura mater. These vary 
considerably in size and number. They pro- 
ject inwards upon the brain, and indent that 
organ more or less according to their size, and 
sometimes they project outwards, and by 
causing absorption of the bone by pressure 
form depressions for themselves, and even wear 
holes in the bone by their outward growth. 
Tubercles of a strumous character are some- 
times deposited in connection with the dura 
mater. The most remarkable example I have 
seen of these morbid tumours is a preparation 
in the museum of King’s College, London, 
taken from a patient who suffered severely from 
epilepsy. é internal surface of the dura 
mater and of the falx is covered with numerous 
tumours of this kind, some of which are nearly 
as large as a walnut, others not larger than a 
small filbert. This specimen belonged to the 
collection of the late Dr. Hooper, who has 
given an excellent delineation of it in his plates 
of the morbid anatomy of the brain. : 
The dura mater participates in the diseased 
states of the cranial bones. Cancer or fungoid 
disease affecting the calvaria or any part of the 
cranial wall which is covered by dura mater, 
will extend to the dura mater and subjacent 
* parts. 
