most important from a therapeutic point of view are sodium, magnesium, iron, carbonic acid, sulphur, and perhaps hydrosulphuric acid. The various substances detected separately by chemists are in their analyses combined by them into various salts-if not with absolute certainty, undoubtedly with a close approximation to it.

These combinations are very numerous, some waters containing from 10 to 20 per cent. of them; yet there are always certain predominating constituents which mark the character of the spring, while many substances, such as cesium, rubidium, or fluorine, occur in mere traces and must be regarded as unimportant.

Mineral waters may be considered, therefore, as weaker or stronger solutions of salts and gases of higher or lower temperature, although the quantity of saline ingredients commonly bears but a very small proportion to that of the fluids containing them. For purposes of therapy they are used either externally in the form of baths or internally as beverages. With regard to the former use—or, to speak technically, balneotherapy-the scope of the present work precludes treatment in extenso. Enough to say that in certain conditions the system is undoubtedly benefited by resort to baths of various characters, especially when accompanied by the accessory aid of well-considered diet and regimen.

The literature connected with the subject of potable waters is voluminous, yet the deductions drawn by various observers touching their efficacy and in relation to the comparative value of natural springs are too frequently colored by individual bias, or based upon too hasty analysis to furnish infallible data or warrant the definite statement possible in ordinary therapeutics. That certain waters charged with foreign ingredients when ingested react upon the system favorably in the case of certain disorders it were futile to deny. Yet even here there are subsidiary considerations not to be ignored; and it is an open question how far the patient may be relieved by the potency of the remedy per se, or whether the collateral aids of environment, climate, altitude, temperature, etc. may not have an important bearing upon beneficial results.

It has been well observed that in the case of water taken in situ the curative atmosphere of the surroundings, the favorable season of the year, the reflex influence of social amenities, and freedom from customary cares, aided by studied regimen under constant medical supervision, play no unimportant part in the alleviation of positive or imaginary disorders. The maxim, "Amuse the patient and let nature work the cure," seems not wholly inapplicable to

many fashionable resorts where a constant round of gayety acts as a practical, though imperceptible, tonic or stimulant upon subjects of certain nervous susceptibilities. These considerations are no less forcible in the case of American "watering-places" than in those of the more famous resorts of Europe.

Various attempts have been made to range mineral waters according to their therapeutic action, their external and internal effects physiologically, and, most frequently, according to their chemical composition. Yet their influence is so dependent upon idiosyncrasy and their constituents so varied that it is wellnigh impossible to select a definite system free from objections, although a scientific classification, uniformly adopted, would undoubtedly promote their rational employment. Many sulphur waters are practically earthy or saline ones, yet the presence of minute quantities of hydrosulphuric acid, an ingredient so palpable as always to attract attention, has determined a classification obviously at variance with natural fact. The general rule has been to class waters under the head of their predominating elements, the desideratum being comparative simplicity untrammelled by theoretical considerations. In this view perhaps the most convenient arrangement of native mineral springs is that subjoined, adopted by Dr. A. N. Bell and widely accepted by writers on therapeutics:

Alkaline. These waters owe their chief therapeutic value to the alkaline salts they contain. They are rich in alkaline carbonates, especially the sodium carbonate. Other substances are included among their ingredients, many of them strongly charged with carbonic-acid gas, which may possibly contribute to their physiological activity.

Saline. These either contain (1) chloride of sodium as the principal ingredient, or (2) are largely impregnated with the sulphates of sodium and magnesium. Several other ingredients enter into their composition, yet their efficacy chiefly depends upon their predominating elements: the second class includes the bitter or purgative waters highly prized both in this country and abroad.

Sulphuretted. The sulphuretted hydrogen present in these waters lends to them their chief therapeutic value. They contain also various sulphides—of potassium, sodium, calcium, and magnesium-together with earthy and other sulphates, which doubtless contribute in a measure to their potency as physiological agents, although their action upon the system is still a matter of conjecture.

Chalybeate. Many mineral springs contain iron, yet in amounts so insignificant as to be of little value to therapy. There are, however, chalybeate waters highly charged with iron salts in the form of the carbonate or sulphate which have acquired a reputation for efficacy in the treatment of certain diseases.

Acidulous.-The valuable property of these springs lies in the superabundance of carbonic-acid gas they contain, to which the solid constituents are subordinate, the carbon dioxide being the important therapeutic ingredient.

Calcareous.-Calcium, in the form of the carbonate, is the valuable constituent of calcareous waters. Besides this substance they contain magnesium carbonate in varying quantities. Their utility as mineral waters has been questioned, many authorities refusing them recognition as therapeutic agents.

The following enumeration of native springs is from the admirable list compiled by Dr. A. N. Bell:

Berkshire, Vermont.

Cañon City, Colorado.
Carlisle, Colorado.
Congress, California.
Elgin, Vermont.
Fry's Soda, California.
Highland, California.
Highgate, Vermont.
Lower Soda, California.
Milford, New Hampshire.
Manitou, Colorado.
Middletown, Vermont.
Napa Soda, California.
Newbury, Vermont.

Perry, Illinois.

Rocky Mountain, Colorado.

Ravenden, Arkansas.

South Park, Colorado.

Sheldon, Vermont.

Vichy, California.

Wilholt Soda, California.

Calcic:

Bethesda, Wisconsin.

Butterworth, Michigan.

Birch-Dale, Vermont.
Clarendon, Vermont.
Eaton Rapid, Michigan.
Gettysburg, Pennsylvania.
Hubbardstown, Michigan.
Silurian, Wisconsin.

Chalybeate:

Abbeville, South Carolina.
Bedford, Pennsylvania.
Blossburg, Pennsylvania.
Cooper's Well, Mississippi.
Esbitt, Kentucky.

Fayette, Pennsylvania.
Gordon's, Georgia.

Summit, Maine.
Sheldon, Vermont.

Thermal Springs :

Agua Caliente, New Mexico.
Arrow-Head, California.
Buncombe County, North
Carolina.

Calistoga, California.

Chalk Creek Hot, Colorado.
Charleston Artesian, South
Carolina.

Des Cahutes Hot, Oregon.

Harbines, California.
Hot Springs, Arkansas.
Idaho Hot, Colorado.
Merriweather, Georgia.
Middle Park Hot, Colorado.
Ojo Caliente, New Mexico.
Paraiso, California.
Passo Robles, California.
Salt Lake, Utah.
Seigler, California.
Skaggs, California.
Volcano, Nebraska.

Warm and Hot, West Virginia.

GROUP VII.-BITTERS.

SIMPLE BITTERS.

Quǎssia-Quǎssiæ-Quassia. U. S. P.

Origin. The wood of Picrana excelsa Swz., a tree resembling the common ash, attaining a height of from 60 to 80 feet (18-24 M.), indigenous in Jamaica.

Description and Properties.-In the shops it is usually met with in the form of chips or raspings of a yellowish-white color. Quassia contains two bitter principles-quassin and picrasmin. It

contains no tannin.

Dose.-10-30 grains (0.6–2.0 Gm.).

Official Preparations.

Extractum Quassiæ-Extrăcti Quăssiæ-Extract of Quassia.-Dose, 1-3 grains (0.065-0.2 Gm.).

Extractum Quassiæ Fluidum-Extracti Quassiæ Fluidi-Fluid Extract of Quassia.-Dese, 10-30 minims (0.6-2.0 Cc.).

Tinctura Quassiæ-Tincturæ Quassiæ-Tincture of Quassia.—Dose, į-2 fluidrachms (2.0-7.3 Cc.).

Gentiana-Gentianæ-Gentian. T. S. P.

Origin. The root of Gentiana lutea L., a plant from 2 to 3 feet high, indigenous in the mountainous portions of Central Europe.

Description and Properties.-It appears in nearly cylindrical pieces or longitudinal slices about 1 inch (25 Mm.) thick, the upper portion closely annulate, the lower longitudinally wrinkled; exte nally deep yellowish-brown; internally lighter; somewhat flexiblk