OCR Text |
Show £508 or THE FL'NGUS ennnmu. or THE Ferrous cement. learned friend Mr. Abernethy, that I think myself called up: on in some degree to extend the Consideration of the subject. Mr. Abernethy conceives that such tumours proceed from an injury of part of the brain, which has terminated in a diseased state of the bloodwessels, similar to what appears in apoplexy ; and that the morbid state increasing, one or more vessels give way, and an eifusion of blood into the substance of the brain ensues. He supposes, that if in this state of the brain there were no opening in the cranium, apoplexy would be the consequence; but that the deficiency of the bone allows the blood to expand and press the brain and its meninges through the vacant space of the bone; that the dura mater soon ulcerates ; and that the tumour pushing through the opening, new increases with a rapidity proportionate to ., that with which the hwmorrhagy takes place Within. I have dissected a case very much resembling that describ< ed by Mr. Abernethy, in which the section of the brain around the root of the tumour shewed many spots of extra‘ vasation; and it would readily occur to any one, that this tumour had been occasioned by one of the larger» vessels giving way, and pouring out a coagulum. But these spots of extravasated blood attend most ulcerations in the substance of the brain. In the first place, I conceive that the deficiency of the skull, and the ulceration of the dura mater, always precede this disease; that it is in consequence of large openings in the skull by the trepan, or the lifting of large depressed pieces (accomu panied by a tendency to ulceration in the substance of the brain), that the pulsation of the brain forces the dura mater against the sharp edge of the bone, when it ulcerates; and then there quickly sprouts up this fungous tunrour from the substance of the brain. Mr. Aberncthy conceives that the bursting of the vessel within the brain is a consequence of the blow; but I have seen the disease arise after a venereal caries of the skull, in which the whole thickness of the bone had, after a great length of time exfoliated. 309 Further, the surface of this tumour bleeds when torn or cut. Not only it bleeds if it be torn oil", but the abraded surface bleeds. This is not like a coagulum. 2. It shrinks and collapses upon death; which is certainly a mark of a part having circulation within it. 3. I have a preparation of this disease, where an ulcer passes from its base into the lateral ventricle, and where the ulcer communicated outwardly, and yet no drop of blood or coagulum was seen upon the surface of the brain, or in the cavities. 4. It is not formed of concentric lamina, as the coagulum of an aneurism is. The blood never bursts from its surface, as it would do even from a venous tumour, which had power in the first instance to burst the membranes of the brain. It is affected like spongy granu~ lation by caustic. A degree of compression, equal to the compression of a considerable artery, will not subdue it when its growth has got head. 5. It has a fibrous structure; and when it is dissolved in death, it hangs in shreds not like a coagulum. Lastly, in the engraving which I have given, it will be seen, that the peculiar disposition to this disease is not shown merely in the tumour, but is evident on the mar- gin, and inner-side of the ulcerated cavity. It is for these reasons that I venture to differ in opinion with Mr. Abernethy, for whose accuracy of observation and abilities I have great respect, heightened by friendship, and a sense of the great improvement I have reaped from his conversation, and from his works. But further, when I was writing upon this subject, with Mr. Abernethy's book, and my preparations of the fungus cerebri before me, he paid me a visit; and his conclusion from our difference was, that we had seen different specimens of tumour issuing from the brain. This conclusion was very agreeable to me, and gives me confidence in stating to my readers the short description of what I have seen, and at the same time to inform them, that there are other distinctions in the nature of this tumour to be observed, which, though I have not seen, they were to at tend to. |