An account of the life, lectures and writings of William Cullen. Vol.1 / by John Thomson.

  • John Thomson
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: An account of the life, lectures and writings of William Cullen. Vol.1 / by John Thomson. Source: Wellcome Collection.

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    of motion is entirely gone. Take these little touches of theo¬ ry by the way, and with the cautions I was just now giving.” 64 2, I say the Brain gives more or less of Sensibility, as it is more or less excited. To explain myself, I need only repeat what I formerly said on the subject of Sleeping and Waking, from which I chiefly take my proofs of the Brain’s being liable to different states of Excitement and Collapse, or of Sensibility and Stupor, states which are different from those of being compressed or free. But taking these prin¬ ciples for granted, I say there are intermediate states be¬ tween sleeping and waking ; and the sensibility is greater or less as the tendency to either happens to prevail. We par¬ ticularly observe such intermediate states in the application of Narcotics, when they produce a degree of drowsiness or stupor; and, therefore, the Sensibility of the Brain may be diminished by the operation of Narcotics and by other causes. There are, however, cases in which our Narcotic medicines have an opposite effect—that is, produce waking and increas¬ ed sensibility. This is commonly explained by a supposed combination in these substances of a stimulant and a seda¬ tive power, and perhaps there is some foundation for this supposition ; but I shall shew hereafter that such a combi¬ nation is not very clearly explained, and that the fact is ex¬ plicable upon a principle different from that of two powers in the same medicine. I go on to mention another piece of theory that is more evident—that Sensibility is increased by an increased distention of the vessels of the Brain. Nothing o indeed is more evident than that the Energy of the Brain, that is, its action in determining the Nervous power into the rest of the system, depends very much upon the fulness and tension of its bloodvessels ; and it is, therefore, to me pro¬ bable, that the degree of Sensibility in the Sensorium will, in some measure, depend upon the same circumstance. It may perhaps be started as an objection to this, that a certain excess of fulness in the bloodvessels of the Brain, seems to