Regarding the Action of Hydrate of Soda,

IN No. 1, Vol. III., of the JOURNAL OF PHYSIOLOGY Dr. Gaskell records some experiments regarding the respective action of antiarin, hydrate of soda, muscarin, and digitalin on the ventricle of the frog's heart. In this paper I record some experiments on the action of soda, ammonia, and potash on the same structure. In most respects my experiments with soda hydrate agree with those of Dr. Gaskell; in some respects, however, my tracings differ from his tracings. These experiments were made with Roy's tonometer. I tied the ventricle to the cannula by a ligature passed round the auriculo-ventricular groove, so that I experimented only with the ventricle. I used dried bullock's blood dissolved in water so as to represent normal blood; to this solution I added saline solution in the proportion of one part of blood to two of saline. Of this mixture I employed three ounces in each experiment. These experiments were made in June. The tracings run from left to right. I find that soda, ammonia, and potash affect the ventricle in much the same way. There are, however, differences in their action. I shall first describe the characters in which they all agree, and then point out in what respect the action of potash differs from the action of soda and ammonia. Ammonia.