The Action of Arseniate of Soda and Arsenious Acid on Frogs

Sydney Ringer, William Murrell
1878 Journal of Physiology  
records some experiments concerning the action of arsenic on frogs. He says, that in about five minutes after injecting it, the animal lies flat with extended extremities, and without breathing. Pinching or other irritation excites neither reflex action nor voluntary motion, though much voluntary power remains, for on lifting the animal, or withdrawing a leg, or turning the frog on its back, it displays active voluntary movements. In a short time, however, the animal becomes completely
more » ... . Arsenic, therefore, paralyses first sensation and reflex action, and sometime afterwards voluntary power. Now paralysis takes place in this order after mechanical arrest of the circulation by ligature, or by excision of the heart. Arsenic being a powerful paralyser of the heart, we were induced to undertake this series of investigations to ascertain whether arsenic paralyses simply by arresting the heart's action. Our experiments show that arsenic does not paralyse simply by its action on the heart, but that, like potash, it has a poisonous action on all nitrogenous tissues, and destroys their function. We commenced our experiments in October, 1877. We first experimented with arseniate of soda, using a solution of the same strength as that employed by Sklarek, but we obtained very different results from those described by him. We then tried arsenious acid dissolved by the aid of a small quantity of soda, and with this form of the drug we obtained effects similar to those recorded by Sklarek. In this paper we shall describe, first the action of arseniate of soda, and then of arsenic, and point out in what respects they differ; then we shall adduce experiments proving that arsenious acid is a protoplasmic poison, destructive of the function of nitrogenous tissue. 16 PH. I.
doi:10.1113/jphysiol.1878.sp000019 pmid:16991254 fatcat:24piuwrqyrc7lnwxxozdi7w5ge