Attention has already been called to water containing iron and to the very widespread belief that iron is a tonic and beneficial. This fact cannot be denied. On the whole it must be said that the valuable properties attributed to medicinal waters are as a rule very grossly exaggerated. Mineral waters are not intended at all as a general beverage to be used every day; they are only to be taken at intervals, and the longer the intervals as a rule the better. It is not a normal condition of affairs to be pouring into the alimentary canal a lot of foreign material which is not indicated in a state of perfect health. The value of a remedy as a rule is very greatly enhanced by its intermittent use, and mineral waters are no exception to this rule. It may be that in many cases the drinking of the waters producing more or less cathartic effects and thus freeing the alimentary canal of objectionable matters does tend to help in the good work of restoring health, but if all the factors which are active in this result are analyzed, it is doubtful whether the waters themselves would occupy a very high place in the scale of remedial agents.