Dr. Heidler considers the Ambrosiusbrunn as bearing considerable analogy to Bruckenau, Bocklet, and the Stahlbrunn at Swalbach; but as far as the chemical composition is concerned, there is much difference, as may be perceived by reference to those springs. Dr. H. prefers the Ambrosiusbrunn for children, and also for adults of very weak and delicate constitutions, as preparatory to the water of the Carolinenbrunn. It is easy of digestion, and may be taken for a long time, without inconvenience. It is very useful in gravelly complaints. The Carolinenbrunn is of more extensive application than the Ambrosiusbrunn; but much less so than the Kreuzbrunn, or even the Ferdinandsbrunn. Experience has shewn that the “_acidulous chalybeates_,” whose properties are exciting and tonic, are much less useful in chronic diseases than those which are solvent, and which produce crises in the course of their operation—especially through the medium of the bowels and the kidneys. The first impression of the Carolinenbrunn on the stomach is excitant and refreshing, like all other acidulous springs. It has been generally used by the inhabitants as common drink; and yet it does not digest so easy, among the invalids, as the other springs of Marienbad—many of them experiencing weight and oppression at the epigastrium, particularly if they are weak and irritable constitutions, or labouring under any congestion or engorgement of the abdominal organs. It is much less aperient than the Kreuzbrunn and the Ferdinandsbrunn—indeed it often confines the bowels, and then the patient must take some of the other waters with the Carolinenbrunn or aperient medicine. This spring is the strongest in iron of all the others. It bears the greatest affinity to Schwalbach and Spa; but is a stronger chalybeate, and contains more carbonic acid gas than they do. It leaves an _après-gout_ of steel on the palate, as also of sulphur.[63] The Carolinenbrunn may be classed amongst the exciting and tonic waters. It moderately excites the circulation and the nervous system, by a transient stimulation, which does not leave a debility behind. Although it is not aperient, it rarely produces astringent effects, like bark, steel and other tonics. It augments the action of the kidneys—and may be said to gently increase the activity of the whole organism, without checking any of the secretions. It is therefore prescribed, with much advantage, in all cases of pure debility, and unattended with any fever or local inflammation. Care ought always to be taken that the bowels are cleared of all impurities before this water is used, and that constipation is guarded against during the course. It is used in baths. The rules for using the waters are not materially different from those enforced at other spas. The season lasts from the beginning of May till the end of September. THE BATHS.