Whether kinovine is itself an available remedy in disease has not yet been determined. It is employed, however, in the preparation of Kerner's pure and impure kinovates of lime.

Physiological Action. - The action of the cinchona barks upon the living organism is very complex: indeed, it is not yet possible to specify, in full detail, either the whole of the effects which the bark itself can produce, or the precise shares which are respectively contributed by the several ingredients. I proceed, however, to give some account, first, of the action of cinchona bark itself, and then of the effects produced by the active ingredients above enumerated.

Action of Cinchona Bark. - The first point requiring consideration is that of the chemical differences between the various kinds of officinal bark which are sufficient to cause diversities in their respective effects. The most important part of this question relates to the differences in the percentage (a) of alkaloids; (β) of tannin; (y) of quinovine; and (δ) of kinovic acid.

(a) As regards the alkaloids, it is found that between yellow bark and red bark there is the following difference: the yellow contains about two per cent. of quinine, and scarcely any cinchonine; while red bark contains upon the whole about an equal quantity of each. Pale bark, in contrast with the other officinal sorts, contains only half the total customary percentage of alkaloids, and what it does contain is chiefly cinchonine. Here it may be noted that the species of cinchona chiefly cultivated in India are the succirubra and the lancifolia; and that the latter is reported to contain a larger proportion than the former both of quinidine and of cinchonidine.

(β) As regards the tannin. Of this, red bark contains about 3.2 per cent., and yellow bark about 2.5 per cent; In pale bark the proportion is considerably less.

(y, δ) The proportions of kinovic acid and of kinovine contained in the different varieties of bark have not yet, so far as I am aware, been exactly determined. The matter is nevertheless one of great consequence. We know at all events from the researches of De Vrij that kinovine is abundant in yellow bark. For reasons which will become evident when the therapeutic actions of the particular ingredients of bark shall have been spoken of, it will be highly interesting to learn whether the officinal pale bark, and other kinds which are weak in alkaloids, are fairly rich either in kinovic acid, or in kinovine,1 since it may sometimes be desirable to seek to obtain the effects of these two last without material admixture with them of the action of the alkaloids, but still in combination with a small amount of tannin-astringency.

The action of the cinchona barks, as such, has never received the kind of investigation which has lately been pursued in regard to the alkaloids; and in the present state of our knowledge there are no means of deciding whether the barks of different species operate in ways which would theoretically correspond with the different proportions of the ingredients they contain. The following facts, in regard to cinchona barks in general, are, however, pretty well established: (1) When given in very large doses, they produce the phenomena which are known as "cinchonism," and which will presently be described under the head of quinine. But for the production of these phenomena extreme doses are required, and long before they commence certain disturbances come into play. (2) Upon the mucous membrane of the alimentary canal, cinchona bark produces effects which are probably quite independent of those induced by the alkaloids, and which are attributable to the astringent ingredients. In the provings of Jorg (undertaken with the object of testing the statements of the homoeopathists), when powdered bark was taken in two-drachm doses, the symptoms were flatulence and eructation, sometimes accompanied by a little nausea, but more frequently by improved appetite. At the same time there was generally some constipation, but beyond this nothing, except that one of the experimenters was troubled with repeated nocturnal erections. This last-named effect will be more particularly noticed when speaking of the action of the alkaloids.

1 It is reasonable to believe that kinovine is decomposed in the gastric juice, with formation of kinovic acid and kinova sugar.

In passing, I must allude to the statement of Hahnemann and of some of his followers, that cinchona bark can produce intermittent fever. This is quite incorrect. No doubt, when taken in large doses by very susceptible people, cinchona may so upset the nervous system as casually to induce a symptom or two of the kind seen in true intermittents. But it is now admitted, even by homoeopathic writers, that no one ever saw cinchona induce a periodic recurrence of attacks such as could in any way fall under the designation of fever. I shall point out, in the section upon quinine, the probable source of this error in observation.

(Concerning this matter, Trousseau and Pidoux speak as follows: "Daily observation, says Bretonneau, proves that cinchona, given in large doses, produces in many persons a well-marked febrile movement. The character of this fever and the period at which it manifests itself vary in different cases. Most frequently tinnitus aurium, deafness, and a sort of intoxication with a slight chill first occur. Succeeding this there is dry heat with headache, which gradually subside with slight perspiration. Under additional or larger doses the fever is increased.

"These physiological effects of cinchona, noticed in the first edition of our Traite de Therapeutique, have been misunderstood and denied by the majority of physicians in this country; since then many observers abroad and at home have testified to the same, and though the authors claimed the honor of a discovery which belonged to Bretonneau, their testimony is none the less valuable; and to-day any physician may, with a little attention, verify the facts on which we here insist."1