FROM the experiments related in Dr. Springsfeld's Commentatio de prærogativa thermarum Carolinarum, &c. which you were so good as to send me some time ago, it appears, that these waters are not only possessed of a very extraordinary power of dissolving the stone, but that in this respect they greatly exceed lime-water.
(A) Thus, Dr. Springsfeld having infused, for 14 Days, in a heat of 96 degrees of Fahrenheit's scale, three pieces of the same calculus, each weighing 30 grains, in eggshell lime-water, the Carlsbad water, and in the urine of one who daily drank this last water, renewing these several menstruums every day, he found, on the 15th day, that the calculus in the lime-water had lost 1 grain, the calculus in the Carlsbad water 6 grains, and that in urine 5 grains.
(B) Again, having divided another calculus into four parts, each of which was reduced to 80 grains, he put the first in oystershell lime-water, the second in Carlsbad water, and the third in the urine of a person who drank this water. After 20 days, during which time the menstruums were renewed every day, and kept in a heat of 96 degrees, the dried calculi had lost of their weight as follows: the first 3 grains, the second 18 grains, and the third 14 grains.
Altho' I make no doubt that Dr. Springsfeld, who appears to be a man of candour, as well as learning, has faithfully related the event of the experiments, which he made; yet either the lime-water he used must have been very weak, or some other mistake must have happened in his experiments: for in all the numerous trials I made, about 15 years ago, of lime-water, as a solvent for the stone, I always found its dissolving power much greater, than it appears in Dr. Springsfeld's experiments. And as in these trials different urinary stones were used, it can scarcely be imagined, that it was owing to the peculiar hardness of Dr. Springfeld's calculi, that the lime-water made so little impression on them. However, to be still further satisfied of this matter, I made the following experiments.
1. I put a piece of a very hard calculus, which I shall call x, weighing 80 grains, in oystershell lime-water, renewing the lime-water every day, and keeping it in a heat between 90 and 106 degrees of Fahrenheit's scale. After 20 days, I took out the calculus; and having set it by for some days, till it was become quite dry, I brushed away all the rotten part of it, which was reduced to a kind of chalky powder, and found that the undissolved part of it weighed 57 grains.
2. At the same time a piece of another calculus, z, weighing 15 grains, was, after a like infusion of 20 days in oystershell lime-water, reduced to 10 grains.
3. I put a piece of z, weighing 14 grains, in a solution of half an ounce of the internal part of Spanish soap in nine ounces of water, and every third day renewed the solution, which was kept in a heat of about 60 degrees. After 14 days, I found the undissolved part not to exceed 11 grains.
4. A piece of a white chalky calculus, y, weighing 30 grains, had near 4 grains of its substance dissolved, by being 14 days infused as above in a solution of soap.
From Nº. 1. above, compared with Dr. Springsfeld's Exper. (B), it appears, that the dissolving power of oystershell lime-water is to that of the Carlsbad water as 23 to 18, supposing the calculi used in these experiments to have been equally easy to dissolve.
Nº. 3. compared with Dr. Springsfeld's Exper. (A), shews, that the dissolving power of a solution of the inner part of Spanish soap, in a heat of 60 degrees, is to that of the Carlsbad water, in a heat of 96 degrees, as 15 to 14.