NERVOUS SYSTEM. (NERVOUS CENTRES. ABNORMAL ANATOMY.) 720E 



substance and passing into the lateral ventricle 

 of one side, and thence through the foramen of 

 Monro into the lateral ventricle of the other 

 side. The convolutions are the next most 

 frequent seat of apoplexy, and after them 

 either hemisphere of the cerebellum, and either 

 cms cerebri. The pons, cms cerebri, crus 

 cerebelli, are much less frequently affected by 

 hemorrhage. These parts are denser in struc- 

 ture and less freely supplied with blood, and, 

 therefore, less prone to apoplectic effusion than 

 those before mentioned. 



Cancer of the brain. Cancer is occasion- 

 ally, although very rarely, found affecting some 

 part of the encephalon ; most frequently it ex- 

 tends into some portion of it from the meninges. 



Andral has given a good history of this 

 diseased condition, founded upon the analysis 

 of forty-three cases.* Of these, the hemispheres 

 were the seat of the cancer in thirty-one, in five 

 the cerebellum was affected, once the meso- 

 cephale, three times the pituitary body, and 

 three times the spinal cord. 



The number and size of the cancerous tu- 

 mors are very various. The cancer may begin 

 in the meninges, and attack the bone on the 

 one hand and the brain on the other; or it may 

 be first developed in the substance of the 

 hemisphere. When the disease is superficial 

 the cranial walls may become extensively im- 

 plicated. I have seen the greater part of the 

 parietal bone implicated in a cancerous tumor. 

 Andral mentions a case in which the frontal 

 and temporal bones were completely destroyed, 

 and another in which the cancer, developed at 

 the inferior surface of the brain, passed out 

 through the foramina of the base of the cranium. 



Cerebral cancer is most frequently of the 

 soft or fungoid kind, but sometimes it occurs 

 in the form of small hard tumours, deposited 

 in various parts of the brain, and separated 

 from the surrounding cerebral substance by a 

 distinct membrane or capsule. Frequently it 

 appears to be primary, or at least there seems 

 no evident connection between it and any other 

 cancerous deposit situate elsewhere. Of An- 

 dral's forty cases only ten were associated with 

 cancer in other situations. 



Tubercle of the brain. The anatomical 

 characters of tubercle of the brain are very 

 definite. The colour is yellow, the more con- 

 spicuous by reason of the white or grey of the 

 surrounding cerebral texture ; the consistence 

 cheesy. Its section affords a smooth and clean 

 surface, but if broken up by the point of the 

 knife, its texture appears to be minutely granu- 

 lar. Sometimes this tubercular matter may be 

 picked out of a very distinct capsule. The 

 tubercles vary very much in size, sometimes as 

 small as a millet seed, frequently the size of a 

 split pea, or even as large as a filbert or a wal- 

 nut, rarely much larger. 



The parts of the brain most frequently af- 

 fected by tubercle are the cerebral hemispheres 

 and those of the cerebellum. The mesocephale 

 and the medulla oblongata are rarely the seat 

 of it. It is generally situated near the surface 



* Clin. Med., t. v., p. 633. 



or near some process of pia mater; conse- 

 quently it is most commonly met with in the 

 grey matter of the brain. 



Cerebral tubercle excites inflammation in the 

 surrounding brain substance, which is then 

 found in the state of red softening; and some- 

 times suppuration may be established, the 

 tubercular matter being more or less broken 

 down and diffused in the pus. It is thus that 

 tubercles of the brain prove so destructive to 

 life. They may remain quiescent and unde- 

 tected and even unsuspected until some irritation, 

 often propagated from the periphery, excites 

 surrounding inflammation, which by reason of 

 the presence of the foreign matter of the tuber- 

 cle, is kept up, and refuses to yield to any 

 measure of treatment. Cerebral tubercle exhi- 

 bits no spontaneous tendency to soften, nor 

 does it frequently degenerate into earthy con- 

 cretions. 



Entozoa. The entozoa found in the brain 

 are the cysticercus cellulose, and the acephalo- 

 cyst, with its denizen the echinococcus. Like 

 tubercles, these are always placed near the vas- 

 cular surface, and they may be said more 

 properly to infest the pia mater than the sub- 

 stance of the brain ; by their growth, however, 

 they encroach more or less upon it. The ani- 

 mals sometimes die, and their containing cysts 

 shrink up and become converted into earthy 

 matter, forming calcareous tumors of variable 

 size in the substance or on the surface of the 

 brain. 



Morbid states of the ventricles of the brain. 

 The diseased conditions of the ventricles of 

 the brain are referable, first, to the cavities 

 themselves ; secondly, to their contents ; thirdly, 

 to their lining membrane and to the choroid 

 plexus. 



The most frequent morbid condition of the 

 ventricles is a state of dilatation, which is always 

 passive, being produced by the accumulation 

 of water in it. This retention of fluid within 

 these cavities appears to be a true dropsy, and 

 is in most cases connected with an external 

 meningeal inflammation in a strumous constitu- 

 tion. It is in children that we most frequently 

 meet with this dilatation of the ventricles, and 

 in them it constitutes the disease called hydro- 

 cephalus internus. In adults it occurs some- 

 times, but extremely rarely. In the former, 

 when the disease is of a very chronic nature, 

 the fluid will accumulate to a very great extent, 

 and enlarge not only the ventricles but the 

 cranium itself to an enormous size. 



In persons in advanced age, in lunatics of 

 long standing, and in old epileptics, we fre- 

 quently see a dilated state of the ventricles 

 from distension by water. This is always asso- 

 ciated with a wasted state of the brain; this 

 fluid, as well as the external fluid, servin^ to 

 fill up the space from which the cerebral matter 

 had receded. 



In all these cases the ventricles which expe- 

 rience dilatation are the lateral ventricles, the 

 third and the fourth. In a very few instances the 

 fifth ventricle has been found similarly dilated. 



The fluid contained in the ventricles is gene- 

 rally a clear straw-coloured serum, varyinw j n 



