Have we two brains or one?

  • Brown-Séquard, Charles-Edouard, 1817-1894.
Date:
[1890]
Catalogue details

Licence: Public Domain Mark

Credit: Have we two brains or one?. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    paralysis, this table gives a pretty large proportion of cases of paralysis of the two lower limbs (23 out of 125). This kind of paralysis, i.e., paraplegia, may be due also to unilateral lesions in a great many other parts of the brain. I am fully aware that, out of more than 70 such cases that I have collected, a great many should not be counted, as the state of the spinal cord had not been ascertained. Still, even in these cases, the symptoms pointed to the brain as having caused the paraplegia. But in a number of cases the spinal cord, being examined, was found healthy, and, therefore, there is no possibility of denying that one side of the encephalon can produce paralysis in both lower limbs, i. e., a direct paralysis and a cross one. The above table shows most decisively that paralysis may appear in one place or another, although due to a lesion in the same part, and that, therefore, it cannot be considered as allied with a loss of function of the injured part. XIY. The most decisive argument against the view that we have but one brain for voluntary movements, comes from cases of destruction, in man as well as in animals, of some parts of the supposed motor centers or conductors, or of almost the whole and even the whole of a hemisphere, without paralysis. It is perfectly well known that, excepting in animals highly placed in the scale of mammalia, we can take away a lateral half of the brain without producing a persistent paralysis. It is, of course, manifest in such a case that all the voluntary movements of the two sides of the body can be performed by one half of the brain. As regards man, facts abound showing that destruction of every individual part of one hemisphere can take place without the disappearance of the voluntary motor functions. Leaving aside cases of tumors or abscesses, there are on record, to my knowledge, more than fifty well-authenticated cases of consider- able lesion or complete destruction of the so-called psycho-motor centers on one side, without paralysis. A good many of the authors to whom we owe those facts are men of high standing, and some are physicians of real eminence. Among the best known I will name Yulpian, R. Bright, Andral, Furstner, Mur- chison, Longmore, Poncet, H. Day, Buys, Magnan, Duplay, R. Boyd, De Fleury, Kbnig, Lecorclid, Campbell, R. Quain.