Accordingly there are cases, in which the evidence from experiments on animals with suspected articles of food is unequivocal. For
- [Footnote: to that of animal poisons, than herbivorous or graminivorous animals; and that the
activity of poisons on different animals bears a ratio in the first place to their relative sensibility, and secondly, to the digestive power of their stomach. I question whether these views will be generally admitted by toxicologists, without much more extensive and more careful inquiries than any hitherto made. [Journ. de Chim. Méd. vii. 214.]
Another singular illustration of the facility with which facts are admitted in proof of the varying effects of poisons on different animals, is a statement by a German naturalist, Dr. Lenz, to the effect that the hedgehog altogether resists the most powerful poisons. He states that he has seen one receive ten or twelve wounds from a viper on the ears, muzzle, and tongue, without sustaining any harm; and that ultimately it kills and devours the snake. He quotes Palias for the fact that it has taken 100 cantharides flies without injury, and says a medical friend who wished to dissect a hedgehog, gave it successively hydrocyanic acid, arsenic, opium, and corrosive sublimate, without being able to kill it [L'Institut. ii. 84]. His countryman Reich, however, contradicts these statements, observing that he has poisoned the hedgehog with hydrocyanic acid, arsenic, and corrosive sublimate, but that doses considerably larger are required for a dog or cat. Ninety grains of medicinal hydrocyanic acid, thirty of arsenic, and twenty of corrosive sublimate, occasioned death. [Annalen der Pharmacie, i. 358.] One of my colleagues having lately quoted Lenz's assertion in his lectures, some of his pupils brought me two hedgehogs to be subjected to experiment. A drop of the pure acid put upon the tongue killed each within a minute.
The following experiments by Professor Gohier of the veterinary school of Lyons are worth mentioning; but in order to be satisfactory would require to be performed in a more consecutive train. Muriate of soda in the dose of two or three pounds causes in the horse great disorder and even death. Calomel has no effect. The juice of rhus toxicodendron has no effect on the solipedes either internally or applied to the skin. Ten drachms of opium cause in the horse tympanitis and stupor, not somnolency. Thirty-six grains of opium had no effect on a dog. Cantharides does not injure the horse in the dose of a drachm, or the dog in that of nine grains. When the sheep swallows yew-leaves it is soon seized with locked-jaw and convulsive movements of the lips and flanks: in the horse they cause dilated pupil, convulsive movements of the eyes, and restlessness: the goat and dog eat them with impunity [Corvisart's Journal de Médecine, xix. 156]: man is severely affected by them. Hyoscyamus, stramonium, hemlock, and other narcotic vegetables, though powerfully narcotic to man, will not affect the domestic animals unless given in doses 100 times as great as those given to man. [Ibid. 154.]
The most important researches I have yet seen in this line of inquiry are those of Professor Viborg of Copenhagen, read in the Royal Danish Society of Sciences in 1792. He instituted a connected series of experiments, expressly to determine how far the effects of poisons on man correspond with those on the lower animals. The results were, that mineral poisons appeared to act nearly in the same manner on all orders of animals, antimonial and barytic salts alone excepted, the former of which acted powerfully on man, the carnivorous animals, and swine, but scarcely at all on ruminating and herbivorous animals, while the latter in doses of a drachm had no effect on horses: That animal poisons resemble mineral poisons in their leading effects on most animals: That the vegetable acrids also act pretty uniformly on most animals: and that of the vegetable narcotics there are few which possess poisonous properties in regard to certain animals only. Yew-leaves kill all ruminating animals, and, notwithstanding Virey's statement, swine, mules, and horses, also chickens; and they produce violent symptoms in geese, ducks, cats and dogs, although Gohier says dogs eat them with impunity. An ape ate a large quantity of the Æthusa cynapium without injury. Dogs took from an ounce and a half to three ounces of belladonna without dangerous symptoms. [Marx, die Lehre von den Giften,—from Viborg's Sammlung von Abhandlungen für Thierärzte, i. 277.]
Professor Mayer of Bonn, in an inquiry into the effects of the Coriaria myrtifolia, found that rabbits are not affected at all by a drachm of the extract of the juice given internally, or applied to a wound; while half a drachm swallowed by a cat kills it in a few hours, and three grains will have the same effect when introduced]*
