Volume 2
Elements of the theory and practice of physic, designed for the use of students / By George Gregory.
- George Gregory
- Date:
- 1829
Licence: Public Domain Mark
Credit: Elements of the theory and practice of physic, designed for the use of students / By George Gregory. Source: Wellcome Collection.
27/572 page 23
![5. In like manner, it becomes necessary to notice a fifth state of the circulating system which is occasionally present in nervous dis- eases; I mean the supply of blood imperfectly oxygenated, and therefore unfit for supporting the functions of the nervous system, This principle, it is true, like the last, is very limited in its applica- tion; but it enters into the pathology of apoplexy, and is the foun- dation of many of our reasonings concerning asphyxia. Some of the gaseous fluids seem to act negatively in occasioning the results above noted. Nitrogen probably is of this number. Carbonic acid gas seems to exert a specific and powerful stimulus on the nerves of the lungs, although it may displace a portion of oxygen, and thus produce a privative effect. All the symp- toms of a congested state of the brain are to be observed under the action of car- bonic acid. We cannot speak so confidently of the effects of hydrogen gas: it seems to excite the sensorium, occasions headache, redness of the eyes, and coma, and probably may become the basis of apoplexy, by occasioning congestion. They all occasion asphyxia. P. I have already remarked, that there are states of disease of the brain independent, as far as we can judge, of the circulating system. SIMPLE COMPRESSION. 1. The first of these, is simple compression. This may arise either from a coagulum of blood, a soft tumour, a bony excrescence, depressed portion of the skull, or the presence of some foreigu body, The effects of pressure vary extremely, according as it takes place suddenly or gradually. In most instances, as already observed, the symptoms occasioned by pressure on the brain par- take of the comatose, or apoplectic character; but instances are upon record, particularly in the case of gradual pressure, where such a state has been followed by symptoms, not of insensibility, but of high nervous excitement—by mania and convulsions. The action of extraneous bodies on the brain, may either produce coma, apo: plexy, epilepsy, mania, or convulsions. ‘This variety may be referred in some to the previous condition of the brain, but it may also depend on the part of the sene sorium immediately impressed. 1t certainly depends in some cases on the degree of compression, because there is sometimes to be observed almost an entire loss of sensation and of the power of voluntary motion, whereas in others, we find reitere ated convulsions, acute headache, and frequently mania inflammatoria. P. 2. There still remains to be stated one principle of very general application in the pathology of nervous disorders. Hitherto we have had some cognizable cause for the symptoms—the effusion of blood, inflammation, or the pressure of a tumour. But itis to be remembered, that there exists an affection of the brain and nerves equally independent of pressure, and of all disturbance in the cir- culation within the encephalon. The best illustration of this prin- ciple is afforded by the phenomena of the narcotic poisons, where coma and convulsions are produced by means, which obviously act on the sentient extremities of the nerves, and which, we may fairly presume, deprive the nervous substance of its mobility, or of ]](https://iiif.wellcomecollection.org/image/b3328975x_0002_0027.jp2/full/800%2C/0/default.jpg)
