Before discussing the rôle of calcium in the etiology of tetany it is important to summarize the present status of our knowledge of calcium in the healthy organism.
To illustrate how minute is the amount of calcium involved in metabolic processes, one needs but consider that the soft tissues contain 0.01 per cent. of the calcium in the body, the remainder forming 7.7 per cent, of the skeleton; thus, a child weighing 10,000 gm. would only have 1 to 2 gm. in the soft parts.
The calcium content of the brain, according to Quest1 is relatively high in early infancy, but diminishes as the child grows older, most rapidly in the first few months, then more slowly. In the fetus he found 0.168 per cent, calcium, in a new-born child 0.107 per cent., in a 4 months child 0.072 per cent., at 16 months 0.074 per cent., and at