In addition to the general therapeutic value ascribed to water there is a widespread belief that certain springs have specific medicinal values. There is perhaps no notion more widely disseminated than this, nor perhaps no one tenet in medical matters which has a greater number of adherents. It is a very common practice to "take the waters" for a great variety of diseases, especially those of a chronic character. Especially efficacious are certain waters supposed to be in rheumatism, gout, dyspepsia, nephritis and many other diseases of a chronic and very persistent character. It will be sufficient to state here that the widespread belief in the medicinal values of waters is not as well founded in fact as it is extensive in belief. That certain waters have medicinal principles may be accepted as beyond contradiction. Many of them are purgative; most all of them are to a certain extent diuretic; and a few contain specific remedial agents such as arsenic and other rare elements such as radium which are highly recommended for certain forms of diseases.