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Letter 7689

Crichton-Browne, James to Darwin, C. R.

16 Apr 1871

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    Is sending notes on blushing. Offers information on physiology and pathology of blushing.

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    Has sent photograph of seven imbeciles in one family.

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[Enclosure: 1]

After reading the paper forwarded I have no hesitation in saying that the theory as to the association of blushing and mental confusion is correct. Indeed it is not a theory but a fact and may be stated much more emphatically than you have ventured to do. The vessels of the brain and head and face all receive the nerves which regulate their contraction or dilatation from the same sympathetic center, the cervical ganglia which are in intimate connexion with the spinal cord. The section of the sympathetic nerve in the neck produces the following among other effects—on the same side of the head as that on which the injury has taken place.

1 Dilatation of blood-vessels (flushing),

2. Increase of Temperature

3. Redness and erection of the ear. (the experiment has of course only been performed on animals).

4. An advance of the third or nictitant membrane over the globe of the eye.

5 constriction of the pupil

6 Contraction of the muscles of the angle of the mouth and nostril.

7 Increase of sensibility

8. Increased acuteness of the sense of hearing.

The temperature within the cranium rises, along with the temperature of its external coverings after the section of the sympathetic. This increase of temperature of course betokens an increased afflux of blood to the brain which up to a point will produce increased sensibility and mental vivacity and beyond this dulling of sensibility and confusion of though. We see this illustrated in the phenomena of intoxication. The first effect of alcohol in those unaccustomed to its use is flushing of the face—along with this there is loquacity, acuteness brilliancy, but the next effect is increase of the flushing, and then we have confusion stupidity—and loss of self-control.

We constantly see the capillaries of the brain and those of the face associated both in states of dilatation and contraction. The first and most important step in an epileptic fit is spasm (contraction) of the vessels of the encephalon, and its first outward manifestation is an intense pallor of the countenance. In meningitis (inflammation of the membranes of the brain) in which we have congestion within the cranium, we have engorgement of the face & ears, suffusion of the eyes, and contraction of the pupils. I may mention in passing in relation to this contraction of the pupil that the delirium in meningitis is generally of a fierce character.

Nitrite of Amyl—discovered by Balard and first described in the Journal of the Chemical Society 1859—has the singular property of producing when inhaled, intense flushing of the head and face. When about five drops are inhaled from an hankerchief, a vivid redness suddenly bursts out on the cheeks, and rushes over the brow, in from thirty to sixty seconds. In experimenting with the Nitrite I have repeatedly noticed that whenever the flushing came out the patients grew stupid and confused and bewildered. They have ceased to give prompt intelligent and coherent answers to questions. One woman who had the Nitrite administered several times assured me. assured me that as soon as she got hot in the face she grew muddled all over. Some experiments with this substance would I think throw valuable light on your researches, but they would require to be conducted with great care and caution, and would not be without danger.

Hydrate of Chloral, introduced into medical use, about two years ago; sometimes when given to people with enfeebled nervous systems, induces excessive flushing of the face. In every case in my experience, in which it has done so it has also at the same time induced mental confusion—in some instances trifling—in others extreme, amounting to a state of intoxication, and accompanied by staggering and loss of control over muscular co-ordination.

No fact in medicine is better established than that there is a close and delicate sympathy between the circulation in the brain and that in the face—and head—allowing of course for the difference of circumstances under which the circulation is carried on in the two. Not only as I before said have they a common center of nervous control, but they have also a common arterial trunk—the great carotid, and direct communication in some parts, for example in the orbit where arteries coming from the interior of the cranium, anastomose with others supplying the skin of the face. The important point to note is however the common nervous center. The muscular fibres that govern the diameter, of the blood vessels, receive their whole nervous supply from the sympathetic system, and consequently all motor influences operating upon these fibres whether derived from mental states or physical excitation are conveyed by the sympathetic nerves. Now the sympathetic nerves which supply the brain and those which supply the face have their centers in the same ganglia, and it is inevitable that an influence of any intensity will be propagated from the one to the other.

Given a mental emotion—say shame or slyness—then an influence created by this emotion is conveyed to the sympathetic ganglia—and from there is reflected, on to the face—producing blushing there—and also back to the brain also, producing blushing there also, betokened by increased agitation. This is a rough way of putting it.

If you care to look into the subject you will find much interesting information—as to the functions of the sympathetic nerves in Carpenters Physiology Sixth Edition 1864. p. 729.

Whatever produces paralysis of the sympathetic in the neck induces hyperæmia of the brain and of the face. Intense neuralgia occasioning flushing of the cheek—is often accompanied by—headache giddiness and a sense of mental oppression.

I have read your remarks on blushing to my sister in-law, one of the best or worst blushers I ever encountered— a young lady very sanguine & sensitive and she pronounces them strictly correct. She says that when blushing she often stammers and does not know what she is saying. I suggestd to her that this was due to a feeling of increased awkwardness knowing that her blushing was observed—but she says, No because she has felt quite as stupid when blushing at a thought in her own room. I can make this young lady blush at any moment by looking at her intently. whenever I do so her manner becomes much embarassed.

Trousseau's cerebral macular are only seen during life. They are in fact those singular red lines and blotches brought out by scratching rubbing or touching the skin.

Erysipelas is in some senses a fair illustration of what you desire to enforce. Occasionally however it produces inflammation of the brain, not by sympathy or consentaneous action but by simple contiguity of tissue, travelling along the orbit into the cranial cavity.

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