The first "empiric" use of calcium for the alleviation of tetany is usually ascribed to Walter Harris. In 1689, in his treatise, "De Morbis Acutis Infantum,"1 he described a case of infantile convulsions and an "accomplished cure with no other medicines than a few ounces of crabs' eyes mixed with crystals of tartar." It is questionable, however, whether Harris deserves the credit for the use of testaceous or shell remedies specifically for tetany. According to Shipley,2 "there was nothing new in the use of alkaline shells and stones in therapeutics. Harris merely increased the doses in which they were given and widened their field of use till it covered the whole field of pediatrics." It is more likely that Harris administered crabs' eyes (gastroliths of the common crayfish) to the little daughter of Goodman James Lowry as a purgative and as an antidote for "acidity of the Humours,"
SHELLING DH. CALCIUM AND TETANY IN FOLK MEDICINE. Am J Dis Child. 1932;44(5):1071-1072. doi:10.1001/archpedi.1932.01950120153012