The attitude and positions, natural and preternatural, of the fœtus in utero, acts of the reflex or excito-motory system / by J. Y. Simpson.

  • Simpson, James Young, 1811-1870.
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: The attitude and positions, natural and preternatural, of the fœtus in utero, acts of the reflex or excito-motory system / by J. Y. Simpson. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    in impressions, made principally upon mucous and cutaneous sur- faces, which impressions being conveyed from these surfaces by afferent, excitor, or ilicident nerves (as they are variously termed) to the spinal centre, lead thus indirectly to many and often complex muscular movements through some of the motory nerves connected with that centre becomhig in consequence secondarily excited. The resulting movements are termed reflex or excito-motoiy, because they are induced by excitations transferred or reflected fi'om one set of neiTes to another, that is, from the excitor to the motory nerves, through an intermediate nervous centre. The movements of the foetus in vitero ai'e of this reflex or excito-motory character. That they are so is, I think, proved by the fact, that in all important points they cor- respond with the most fixed characteristics of other undoubted forms and varieties of reflex or excito-motory muscular actions. The prin- cipal characteristics of true reflex movements consist,—1. In the anatomictd conditions under which they are capable of being per- formed; 2. in the origin and character of the movements them- selves ; and 3. in the physiological object or objects with which they may be performed. I proceed to show briefly, that in these various particulars the movements of the foetus in utero correspond to the proper characteristics of true reflex or excito-motory move- ments. 1. Tlie Anatomical Conditions under tvhich the Movements may be jjerformed.—Dr Hall and others have shown, that true reflex or excito- motory movements persist in decapitated animals, when all influence of the brain, and consequently of sensation and volition, is necessarily removed. In instances of paraplegia in the human subject, de- pendent upon complete destruction and division of the spinal cord in the dorsal region, and hence when the agency of the brain was entirely cut off, reflex muscular movements sometimes remain in the muscles of the lower extremities, and are capable of being excited, sometimes violently, by slight irritations applied to the soles of the feet, &c.—the patient seeing, but not feeling, or being otherwise aware of the resulting movements in his own limbs.^ That the foetal move- ments are of the same character, is so far proved by the anatomical fact, that they may occur and go on during the period of intra-uterine life, and even for a day or two after birth, when, from malformation, the brain is entirely absent. The histories of cases of anencephalous monsters show that the intra-uterine movements are the same with them as with other children; and I have seen one survive for thirty- six hours after birth, performing various excito-motory movements during that time,—swallowing, crying, and moving the limbs when ' Cases of the same kind have been recorded by LaHemand, St Hilaire, &c., &c. Ree Dr Hall's Work, p. 134 ; or St Hilaire's Histoire des Monstruosites, Voi. II. C