Note 33 — Chapter III · ORGANISM, ORGANIZATION, AND ORGANIC SUBSTANCE.

M. Fernand Papillon has shown that animals may be fed with food deprived of phosphates of lime if its place is supplied with magnesia, strontia, or alumina; they make their bones out of these as out of lime. But no such substitution is possible in muscle, nerve, or gland; we cannot replace the phosphate of magnesia in muscles by the phosphate of iron, lime, or potash, as we can replace the iron of a wheel by steel, copper, or brass.