NERVOUS SYSTEM. (NERVOUS CENTRES. ABNORMAL ANATOMY.) 715 



the spinal canal. The softening which results 

 from decomposition, in genera!, 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 fcetid. 

 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- 

 scribed 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 

 rare 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- 

 rious sizes, each of which is generally enclosed 

 in membranous cyst. 



Cancer of the cord is a lesion of extremely 

 rare occurrence. Ollivier 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 

 diathesis 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- 

 branes. The remarks already made with re- 

 ference to the membranes of the cord apply 

 equally to those of the brain. The latter mem- 

 branes, however, are more frequently found in 

 an abnormal state than the former. 



The dura mater. There may be a general 

 or partial deficiency of the dura mater and of 

 the other 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 

 or strumous disease of the bones ; or, inde- 

 pendently of diseased bone, us an effect of the 



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 potassiu m . 



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 

 calvana 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. W r hen, 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. The 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. 



