The hand : its mechanism and vital endowments, as evincing design / by Charles Bell.

  • Charles Bell
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: The hand : its mechanism and vital endowments, as evincing design / by Charles Bell. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    Some cruel experiments have been made, which, for whatever intended, illustrate the necessity of closing the top of the wind- pipe during exertion. The wind-pipe of a dog was opened, which produced no defect until the animal was solicited by his master to leap across a ditch, when it fell into the water in the act of leaping; it failed in its leap, because the muscles which should have given force to the fore-legs lost their power by the sudden sinking of the chest. This experiment is sufficiently repugnant to our feelings; and I need not offend the reader by giving instances in further illustration, from what sometimes takes place in man.] Kelation between the Skeleton of the Bird, and its mode of producing its Offspring.—Having, in the earlier part of the volume, noticed some of the more remarkable peculiari- ties of the skeleton of the bird, we may take this opportunity of observing the relation between its general form, and one of its principal functions. Putting out of the question, for the present, digestion and respiration, functions necessary for pre- serving the life of the individual, the continuation of the species is the next in importance. If a bird is to be buoyant and cap- able of flying, it cannot be viviparous. We have seen that a full stomach impeded the flight of a carnivorous bird; now, from that it is evident that it could not have carried its young within it. Is it not curiously provided, then, that the bird shall pro- duce its offspring by a succession of small eggs ; and that these shall accumulate in the nest, instead of growing in the body 1 In short, it requires no argument to prove that the hollow bones of the skeleton, the extension of the breast-bone, the air-cells, the quill-feathers, the bill, and the laying of eggs, are all in necessary relation to each other. Of the Kangaroo.—Since we have spoken of the adaptation of the skeleton of the bird to its mode of producing its young, we may, for the same object, advert to the subject in a quadru- ped. In the mammalia, there is no deviation from the general form of the skeleton more extraordinary than that in the kan- garoo ; and there is, at the same time, a remarkable peculiarity in the manner in which it produces its offspring. Instead of remaining within the mother for the usual period of gestation, the young, by a singular process, not perfectly understood, is excluded, and found attached to the teat there, covered by an p