be given to a child in a table-spoonful of this solution, either as an absorbent, as an antacid, or as an aperient, &c.

The spas themselves are generally resorted to between the months of May and October (inclusive). The course lasts from three to six weeks. Their effects invariably continue for a long period, and the most successful cures frequently take place months after the patients have rejoined their family circles. When immediate improvement ensues, it is often of a less durable character. This lasting efficacy particularly adapts them for the treatment of chronic diseases. In most spas, bathing and drinking of the respective springs take place. Some, however, are merely employed internally, others only externally.

The mineralised mud of some is used separately as a highly curative external remedy; in others, the abundant evolution of carbonic acid serves for general and local gas baths. Where the temperature is too high, ingenuity is taxed for contrivances calculated to lower the heat, without altering the composition of those ingredients partially held in solution by the high temperature. If the temperature is too low for bathing, the bade-meister (bath-master) will show you in one place how the baignoires are warmed by subterranean steam, so that the spring may not lose its carbonic acid and have important substances precipated by being heated. Another will explain that warm water is mixed in his baths in such a proportion with the spa water as not to impair its properties, &c. At others you have douches of various height and power. In some you will see ascending douches, to which many cures are attributed, particularly in several diseases of women. In others again, friction is employed with the douche as a great auxiliary to the medical treatment. (This is particularly well understood and unsurpassed at Aix-la-Chapelle.) In fact, when you visit any spa, you will be astonished at the manner in which every particle of the natural gift is brought to bear upon diseases. If the source be on a higher situation than the baths, you will see this taken advantage of to fill the baths by pressure from below, so that the water flows upwards in a wave-like manner. You see a shaft constructed in which the water rises and is made to splash over and to fill the circumvenient air with its vapour and exhalations for medical purposes. The quantity of the water taken internally varies considerably, and as a rule is gradually to be increased.

Generally, a band begins to play about six in the morning, waking the visitors from their slumbers. In the intervals of

drinking, they take walking exercise for about a quarter of an hour. About an hour after a light breakfast, the baths are taken. The diet is regulated according to the nature of the spa. The curative power seems to be evolved by a slow reaction, which the ensemble of the healing influences produces in the human system. If this reaction is speedily exhibited by signs of a violent revolution, as headache, giddiness, depression, lassitude, restlessness, want of appetite, obstruction or diarrhoea, distention of the abdomen, feverishness, &c., immediate discontinuance of the course is necessary.

The course might be resumed as soon as a more favourable impression can be reckoned upon. Bath eruption,' occasionally appearing after a few weeks, and then disappearing without medicinal aid, is considered a favourable sign.

Both the spas and mineral waters, however useful in chronic, must be entirely avoided in acute diseases, in inflammation of vital organs, inflammatory fevers, &c. They are also contraindicated in hectic fever, in formed tuberculosis, in carcinomatous degenerations, in aneurisms, in congestion of the lungs or brain, &c. In fact, before recommending a spa, the subsequent reaction and unfailing excitement must be taken into almost more serious account than the direct influence itself.

LECTURE II.

THE springs furnish a natural point of classification by their varying temperature. The more a spa approaches the temperature of the blood, the less animal heat is withdrawn by the contact, and the greater the perception of warmth. For convenience sake let us designate, with Vetter, those springs having a temperature below 66° Fahrenheit, krenæ, or cold springs, and those of which the temperature exceeds 95° Fahrenheit, therma, or hot springs. Those that range between 66° and 95° Fahrenheit, may be considered as of intermediate temperature, still depriving the body of some heat, but unable to display the medicinal effect of cold; they are designated as pega.t Mineral waters, without reference to temperature, are also termed pega.

Another natural division may be derived from their local variations, which do not fail to exercise a considerable influence on their medicinal efficiency. Their respective altitude modifies the atmospheric pressure, and displays properties of its own.

The diminished pressure and greater purity of the air in higher situations invigorate and stimulate the weakened nervous system, and diminish passive pulmonary blennorrhages, whilst these places would disagree with persons of irritable thoracic organs, and might excite hæmoptysis, congestion, or inflammation, where a tendency to such diseases already exists.

It has been calculated that the warmth of the air diminishes by 1o Reaumur for every 500 feet of height. But however applicable this law may be in the higher regions, it is less so nearer the earth, the temperature being modified by the direction of the mountains, geographic latitude, and many other circumstances.

It has been assumed, that the whole mass of water on the globe remains constantly of the same amount, though undergoing various changes of form by atmospheric influence. The water attracted and imbibed by the surface of the earth, penetrates to

From κρnn-source.

From ny-spring, salient water.

different depths according to the more or less yielding and porous character of the recipient layers. It then collects in the interior and begins its solvent and chemical action on the surrounding

strata.

It is of importance to consider whether a spring has a merely local origin, or whether it owes its existence to the general character of the mountainous formation.

Thus, most acidulous and thermal springs can be traced to certain characteristic mountain chains, whilst sulphureous and chalybeate springs are mostly independent of the general character of a region, and seem to stand as isolated products of local

causes.

The volcanic processes in the interior of the earth drive mighty rocks of basalt out of the depth of the sea, inflame strata of coals, inundate whole regions with lava and ignited substances, and shake the highest and firmest mountain ranges, and all this free from the various forces and elements acting in the atmosphere of the surface. Fire alone could not accomplish these processes without the co-operation of water.

The contact of the two powers, however, produces vapours, which, by expanding, burst the opposing layers of the earth and discharge streams of lava and of basalt.

If the vapours are pent up, earthquakes necessarily ensue. Should they, however, find no resistance, they form gaseous products and stream out as carbonic acid, sulphuretted hydrogen or nitrogen. To these gaseous streams the thermal and acidulous springs seem to owe their origin.

The volcanic character is probable, from their situation being mostly near active or extinguished volcanoes. Vesuvius is surrounded by thermal springs. The mightiest volcanic mountain chains of Europe are accompanied by powerful thermal and acidulous springs.

A relation, no doubt, exists between earthquakes and Thermæ. It is asserted that those regions are less exposed to earthquakes which possess volcanic springs-for instance, North Bohemia, the Rhine and Taunus regions. Such mountain chains, in which no eruption of lava, basalt, hot vapours, or carbonic acid, has taken place, are said to be more exposed to earthquakes. During the earthquake of Lisbon, that part built on limestone suffered more than the adjoining Belem, partly built on basalt.

Of all the earthquakes that took place in January and February 1824, from the foot of the Saxon mountains to the Elnbogner

kreis, only two German miles from Carlsbad, nothing was felt in Carlsbad itself. On the other hand, whilst an earthquake took place at Lisbon in 1809, the Schlossbrunnen disappeared, but returned in 1823 with a lower temperature.

Through the earthquake of 1692, the water of the Pouhon, one of the springs of Spa, near Liége, became clearer, of a stronger taste, and more abundant. Sometimes, however, earthquakes are only perceived in the environs of hot springs, whilst the flat country is spared.

Most remarkable are the changes that took place on November 1, 1755, when one half of Lisbon was destroyed by an earthquake. Between eleven and twelve in the morning, the chief spring of Teplitz began to get turbid, and to discharge for a few minutes a dark yellow liquid; and after having ceased running a short time, it burst forth with such violence and abundance, that all the basins overflowed. At first it came out turbid and yellowish-red, but regained its former transparency after

about half an hour.

A few days later, on the 9th of November, in Canstadt (Würtemberg), near the mineral springs, two such violent concussions took place, that an adjoining house sank several feet with a loud crash.

The hot springs generally arise out of granite, gneiss, and other volcanic kinds of mountain, frequently near basalt or transition rocks of analogous formation and composition, as porphyry, greenstone, and grey wacke.

Directly out of gneiss, granite, and greywacke, or in their vicinity, arise the springs of Pfeffers, Leuk, and Bormio, in Switzerland, Warmbrunn, in Silesia, most of the hot springs of Hungary, Styria, Salzburg, &c.

Even when Thermæ seem to spring up out of strata of red sandstone or shell-lime, as happens in several springs of the Vosges, in the ramifications of the Black Forest, and the mountains of Nothern Switzerland, this latter formation only seems to form a sort of covering for the deeper primary mountain-masses.

The warm springs of Baden, near Vienna, arise out of tufaceous* lime.

The primary mountains do not seem, however, to be the proper focus of the thermæ, but rather a means of their connection with the volcanic processes in the interior; for the springs mostly come

* Tufa is a clayey fossil, mostly porous, ashy gray, and consisting of loose particles of lime; its origin is volcanic.