This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
If 3/4 gr. of oxide of copper be injected under the skin of a rabbit, there will quickly follow unsteadiness in walking, which will gradually pass into complete motor paralysis: the respirations and pulse become feeble, and muscular irritability becomes less, till finally death occurs from paralysis of respiratory muscles (Harnack: Schmidt's Jahrb., 1874). Falck noted very similar effects, with fall of temperature and progressive general paresis, ending in death from cardiac palsy, after hypodermic injection of sulphate, nitrate, and chlorate of copper (Deutsche Klinik, 1859); sensation was unimpaired, and the paralysis was limited to striped muscular tissue.
It has been remarked that many emetic medicines, e.g., antimony and apomorphia, produce also muscular paralysis, and there may be some direct connection between it and severe vomiting: in Falck's experiments, however (with hypodermic injections), vomiting was not produced. In cases of acute copper-poisoning in men the nerve-symptoms are such as headache, giddiness, prostration, restlessness, tremor, subsultus tendi-num, convulsion alternating with stupor or comparative clearness of mind, and sometimes a motor or sensory palsy, partial and temporary in character: such symptoms are mainly secondary to the gastric irritation.