A practical treatise on the diseases of children / by James Stewart.

  • Stewart, James, 1799-1864
Date:
1841
Catalogue details

Licence: Public Domain Mark

Credit: A practical treatise on the diseases of children / by James Stewart. Source: Wellcome Collection.

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    already prepared for it by the mother, and that when this sup- ply ceased, an instinctive feeling, analogous to hunger, took place in the chest, by which the child naturally sought for air to supply the existing want. The brain excites the motion of the chest, thus preventing the fatal effects that would follow a quiescent state of the lungs. This appetite for air commences at birth, from the excited circulation arising from the struggles of the child; a quantity of blood is thus sent through the lungs, and becomes the direct cause of the desire.* Haller ascribed it to the habit of opening the mouth while in the uterus, in swallowing the liquor amnii. When this mo- tion is repeated, on the child’s being ushered into the world, the air finds its way in, and passes directly into the lungs; blood is distributed through them on their expansion, and a continual supply of air is required to prevent the blood from stopping in its progress from the right to the left side of the heart.t Darwin adopts a like view of the subject in reference to the habit of moving the mouth in the uterus; but this cannot, _ he thinks, be the sole cause of the first inspiration, for breathing and deglutition are different acts. The foetus, at birth, expe- riences an uneasy sensation from the want of air, for the relief of which, all the muscles of the body are thrown into action, and those of the thorax, together with others, by which the uneasiness is relieved.{ The French physiologist, Adelon, supposes that the succes- sive developement of the lungs and their appendages predispose them to the act of respiration.. As the lungs increase in size, and the pulmonary vessels enlarge, the ductus arteriosus be- comes less, whereby the lungs are prepared, on their being properly excited, to discharge their proper functions. The con- tractions of the uterus, also, prepare the foetus for the new change, by pressing the blood out of the placenta, and thus de- ranging the circulation. By this derangement in the distribution of the blood, an additional quantity of blood is sent to the lungs. A new impression is then made on the child by the action of the external air; its coldness and weight make a painful sen- sation on the skin and other parts of the body. These impres- sions are conveyed to the brain, and reflected to the different parts of the muscular system, through the nerves; the muscles of inspiration, as well as the others, receive this impression, transmitted by the nerves, whereby they are excited into contraction.§ * ‘Whyit on Vital Motions, sec. 9, p. 11]. + Elements of Physiology, viil. 5, 2. t Zoonomia, vi., sec. 16. § Physiologie de l’Homme, p. 20.
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