On the influence of physical agents on life / by W.F. Edwards ; tr. from the French by Dr. Hodgkin and Dr. Fisher ; to which are added, in the appendix, Some observations on electricity, by Dr. Edwards, Pouillet, and Luke Howard ; On absorption, and the uses of the spleen, by Dr. Hodgkin ; On the microscopic characters of the animal tissues and fluids, by J.J. Lister and Dr. Hodgkin ; and some notes to the work of Dr. Edwards.

  • Edwards, W. F. (William Frédéric), 1777-1842.
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: On the influence of physical agents on life / by W.F. Edwards ; tr. from the French by Dr. Hodgkin and Dr. Fisher ; to which are added, in the appendix, Some observations on electricity, by Dr. Edwards, Pouillet, and Luke Howard ; On absorption, and the uses of the spleen, by Dr. Hodgkin ; On the microscopic characters of the animal tissues and fluids, by J.J. Lister and Dr. Hodgkin ; and some notes to the work of Dr. Edwards. 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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    are the only influences which have been hitherto ascer- tained with regard to the developement of these animals. There is another which I have endeavoured to determine, and to which I have been led by my experiments on the adults: it is, the effect which atmospheric, compared with aquatic respiration, exercises on the form of these animals in their earliest age. The difference which these two modes of respiration occasioned in the activity of the adult animal, induced me to conceive, that limiting the tadpole to aquatic respiration would tend to continue its original form. With this view I procured a tin box, divided into twelve compartments, each of which was numbered and pierced with holes, so that the water might readily pass through the box. A tadpole, (which had been previously weighed) was put into each compartment, and the box was then placed in the river Seine, some feet below the surface. A larger numbei was at the same time put into an earthen vessel, taining about four gallons of Seine water, which was hanged every day. These tadpoles were at liberty to rise to the surface and respire air, and they soon went through their metamorphosis. Of the twelve placed in the box under water ten preserved their form, without any progress in their transformation, although some had doubled, and others trebled their weight. It should be observed, that at the time when the experiment was begun, the tadpoles had acquired the size at which the change is about to take place. Two only were transformed, and this very much later than those which, in the earthen vessel, had the liberty of respiration in air. The want of atmospheric respiration appeared here to have a marked influence, but we had not the means of accurately informing ourselves of one very influential cir- cumstance, that is, the supply of nourishment. In the river the water is renewed incessantly; and frequently ve-