Studies on the action of mercury

Abstract

Observations on the pharmacology of mercury were made, with special reference to its influence on the circulation and respiration. Mercury in a concentration of 1:5000, in the form of the benzoate, succinate and acetate, was injected intravenously into dogs and cats under ether or ether-paraldehyde anesthesia.

Small doses of mercury frequently produced pronounced changes in the circulation as well as respiration. One and a half to two milligrams per kilo caused stimulation of respiration. Frequency and particularly depth of respiration were increased shortly after the administration of the salt was begun and the effect sometimes persisted for several minutes after the injection was discontinued. Larger doses, however, produced the opposite effect. Respiration was also depressed when the injection of a stimulating dose was repeated several times, thus indicating cumulation.

The effect on the circulation was more complicated. Small doses usually produced a temporary rise in blood pressure of about 8-10 mm. Hg, but in several experiments no change was observed. When small doses were repeated so that the total amount injected was 4-5 mg. of mercury per kilo, depression of the circulation was observed, thus showing cumulation as in the case of respiration. The changes produced usually consisted of a sudden drop in blood pressure and slowing or arrest of the heart which lasted in some experiments thirty seconds. This was followed by recovery, the blood pressure rising rapidly and attaining even a greater height than that before the injection. Very often the blood pressure remained at the new high level for some time and then descended again, but the descent was gradual. The sudden fall in blood pressure was a frequent occurrence, however, in a number of experiments, and in a few cases no recovery took place.