A treatise on the medicinal leech; including its medical and natural history, with a description of its anatomical structure; also remarks upon the diseases, preservation and management of leeches / [James Rawlins Johnson].

  • Johnson, James Rawlins, active 1792-1827.
Date:
1816
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on the medicinal leech; including its medical and natural history, with a description of its anatomical structure; also remarks upon the diseases, preservation and management of leeches / [James Rawlins Johnson]. Source: Wellcome Collection.

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    irregular and indistinct, and the Leech died. On holding up the IL vulgaris to the light, these movements may be distinctly seen even with the naked eye, the pulsations being about eight in a minute. I have at different times ])laced tlie most transparent of the II, vulgaris under the microscope, but never yet could trace any central organ of the vascular sys¬ tem. ^Ve find, however, in a paper by Du- rondeau, that the Leech (H. medicinalis) is described as having a heart, which is said to be a fleshy pouch, in figure conical, but irre¬ gular ; attached to the back by large vessels, but free and floating at its point.^ A heart answering to this description I have never yet observed. Sir Everard Home, speaking of the circu¬ lation of the Caterpillar, remarks that the blood is carried from one end of the body to the other by a species of peristaltic motion, in a tube, which may be either called Heart