Lead-poisoning in frogs / by John J. Mason.

  • Mason, John J.
Date:
1877
Catalogue details

Licence: Public Domain Mark

Credit: Lead-poisoning in frogs / by John J. Mason. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the former experimenting with the nitrate of silver, and the latter with arsenic, both employing the frog. This experiment I have often repeated, and, although from twelve to twenty-four hours are required for the action of the poison to manifest itself, its effects are constant in this species (Eana Temp.). II. Chronic Poisoning.1—The more gradual absorption of lead through that here important organ of respiration, the skin, is followed by symptoms which differ widely from those noted ajbove. In 1871, E. Heubels gave, at short intervals, small doses of the acetate of lead to eight dogs, during periods varying from two to eight weeks. Wasting and paresis of the muscles of the posterior and anterior thoracic regions and of the posterior extremities resulted, but no typical lead pa- ralysis was observed, nor were the electrical reactions given. The above are the latest, and, as far as I can ascertain, the only published experiments, made with the object of causing the symptoms of chronic lead-intoxication in animals. Experiment 2. March 22, 1876.—Four small frogs {Eana Temp.) are placed in a glass globe containing: water, 24 fl. oz.; acetate of lead, 1 gr. 26th.—ISTo change observable. %8th.—Frogs lively. Solution made stronger by addition of seven grains of the lead salt. 2dth.—]STo effect observable. April 3d.—One frog motionless. Posterior extremities paralyzed. Anterior extremities respond to the will. All the muscles of the posterior limbs respond far better to the action of the voltaic than to that of the faradaic current. Division of the spinal cord causes no movement in the lower limbs. Direct irritation of the sciatic nerves by electricity gives rise to no muscular contraction except in the peroneal muscle of one leg, causing slight flexion of the foot. Heart normal in size and action. The faradaic current used in these 11 use the word chronic on account of the longer time whicli elapses before the poison affects the system, and of the constancy of the paralytic symptoms. 2 Pathogenese und Sy nip tome der chronischeu Bleivergiftung. Ex- perimentelle Untersuchungen,