Nitromuriatic Acid is probably next to the mercurials, in Cholagogue power, of all the medicines which operate by a special influence on the secretory function. The same remark, as to the greater Cholagogue efficiency of internal than of external application, may bo made of this remedy as of the mercurials. For an account of its properties and uses, see vol. i. p. 373.

Chlorine-water, and the compounds which chlorine forms with the alkalies, are supposed to have some Cholagogue power. (See vol. II. p. 374.)

Aloes has, I think, undoubtedly a stimulant influence on this function, of which a strong proof is afforded, in its frequent efficiency in restoring the suspended secretion of bile in jaundice, sometimes even when mercury has failed. (See vol. II. p. 528.)

Dandelion or Taraxacum is supposed to promote the secretion of bile, and to have an alterative influence over the liver, and hence is much used in cases attended with a deficiency of that secretion, and in chronic inflammation of the organ. Though I have employed the medicine very often and freely in these affections, I confess that I feel quite uncertain in what degree to consider it efficient; for, having almost al-ways given it with mercury or nitromuriatic acid, I have found it difficult to decide how much of the good effect was ascribable to these medicines, and how much to the dandelion. I am, however, inclined to the opinion, that it has some stimulant influence over the hepatic function.

Leptandra (U. S.) has considerable reputation as a Cholagogue. its officinal history is somewhat curious. introduced, with the name of Veronica, into the secondary catalogue of the first edition (a.d. 1820) of the U. S. Pharmacopoeia, it was continued in the same position in the second edition (1830), was omitted altogether in the third and fourth editions (18-10 and 1850), and was finally readopted in the fifth or present edition; and so great was the change of opinion in its favour that, instead of being put into the secondary catalogue, it now holds a place in the primary. it is the root of Veronica Virginica of Linnaeus, Leptandra Virginica of Nuttall, a perennial herbaceous plant, growing in rich woods, and highland meadows throughout the U. States, east of the Mississippi. The vernacular name of the plant was formerly Culver's physic, but this has given way to the scientific title, which is now generally used in common language. The stem is simple, smooth, erect, three or four feet high, having leaves in whorls, and ending in a spike of white flowers.

The root, or more properly the rhizome or root-stalk, is several inches long, from two to four lines thick, sometimes branching, with numerous long slender radicles. As in the shops, it is usually in broken pieces, an inch or more long, either beset with radicles, or rough with their stumps when broken. They are very hard, of difficult fracture and of ligneous consistence. The colour of the rhizome is a dark-brown externally, but lighter within; that of the radicles almost black. The odour is not disagreeable though faint; the taste bitterish, somewhat nauseous, and slightly acrid. it yields its virtues to water and alcohol. A proximate principle, to which the name of leptandrin has been attached, has been extracted from the root by Mr. Wayne, of Cincinnati, who believes it to represent the activity of the medicine. it is in acicular crystals, somewhat bitter, and soluble in water, alcohol, and ether. For the mode of extracting it, the reader is referred to the U. S. Dispensatory, 12th edition. Leptandrin, however, is not isolated for use. Besides this principle, the root contains also a volatile oil, and, according to Prof. F. F. Mayer, of New York, a peculiar glucoside, bearing a close resemblance to senegin, or the acrid principle of seneka.

The root is said, when fresh, to be violently cathartic, and sometimes emetic; when dried, to be much milder and less certain. Having never employed it, I am unable to say anything of its remedial character from observation; but the "Eclectic" practitioners, who make great use of it, believe it to possess extraordinary Cholagogue powers, and, on this account, to be a good substitute for calomel in all hepatic affections in which an increased secretion of bile is indicated. Their practice has been imitated by many regular physicians; and I have heard from such a source strong testimonials in support of this view of its powers. The "Eclectics" use a resinous preparation made by precipitating the tincture with water, which they have improperly named leptandrin; as this title should be confined to the pure active principle; while the resinous precipitate referred to is complex, containing probably an inert resin as one of its ingredients, and an uncertain portion of the really active matter of the root. The dose of the powder as an aperient Cholagogue is from twenty grains to a drachm, that of the precipitated impure resin from two to four grains. A fluid extract has been prepared, of such strength that a fluidounce of it represents a troyounce of the root, and the dose of which, therefore, is from twenty to sixty minims.

In relation to the therapeutic uses of the cholagogues, all that is necessary has been already stated, in the remarks made upon mercury in general as an alterative (see II. 264), and upon calomel as a purgative (II. 561). it may be proper to notice here one effect of these medicines, which, though not directly therapeutic, may be taken advantage of for the promotion of the action of other medicines. A congested state of the portal circulation necessarily impedes the operation of medicines through absorption from the alimentary canal, as the fulness of the capillaries resists the entrance of substances into them. Consequently, the cholagogues, by unloading this circulation, through increase of the hepatic secretion, and perhaps an increased movement of the blood through the capillaries of the organ, facilitate the absorption of medicines from the primae viae, and thus promote their action on the system.