The word "Kina," in old Peruvian, signifies "bark"-Kina-Kina, "good bark."
Linne named the tree "cinchona" in honor of the Countess of Chinchon, who first brought the bark to Europe. The tree belongs to the family Rubiacece. There are at present a large number of varieties possessing the remedial bark. Since 1854 cinchona has been cultivated with magnificent success in Java, Ceylon, and Hindustan, and the greatest part of it now comes from these countries. The following data in this regard are from Moens. In the year 1880 there was exported from-
The same writer has published an excellent work on the cultivation of cinchona in Asia, and he describes as the most useful species: Cinchona succirubra, Pav.; the different C. Calisaya Wedd.; C. officinalis L.; and the C. lancifolia Mutis. The bark should contain at least 5 per cent, of quinin and its allied alkaloids.
The chief constituents of Peruvian bark are: Quinin (C20H24N2O2). This is a biacid base. Its anhydrid is a white, amorphous substance of very bitter taste. It is but only slightly soluble in water (1 part in 400 of cold or 250 of boiling water). It forms crystallizable salts which are readily soluble in water, and which are, therefore, employed in therapy.
Cinchonin (C10H22N20). Chinidin}.
} isomeric with quinin. Chmicin }
} isomeric with cinchonin.
Chinovin (C30H48O8), a bitter tasting glucosid.
Cinchonic acid (C7H1206), associated in the bark principally with quinin. Cinchotannic acid.
Chinoidin is an amorphous decomposition product obtained in the preparation of quinin. Its constitution is very variable.
Of all these, quinin and its salts possess the greatest therapeutic value. They are, therefore, the most commonly employed, both in a curative and prophylactic way.
The manner in which quinin acts in malaria has been set forth by us as follows*:
"The effect of quinin on the malarial parasites has been studied both by Laveran himself and other investigators. Laveran made his investigations in this way: He prepared two blood specimens simultaneously from a patient. He examined one as it was, the other after treatment with a very dilute solution of quinin. He found that the parasites in the control preparation continued actively motile for some time, while in the quinin preparation they lay still and lifeless. From this the direct poisonous action of the drug on the parasites seemed evident.
Java.........................................123,941 kilos bark
English India..................................208,056 " "
Ceylon........................................526,381 " "
"Later experiments confirmed this occurrence, but they limited its significance, inasmuch as they demonstrated that the addition of other indifferent substances would also kill the parasites: Marchiafava and Celli, for instance, found that the parasites lost their motility when a normal salt solution or distilled water was added to the preparation. Moreover, Grassi and Feletti showed that when malarial blood was shaken for an hour in distilled water and injected into a healthy man, no infection resulted on account of the destruction of the parasites by the previous procedure.
"After direct investigations had proved unsuccessful I undertook to study the blood of patients treated with quinin, paying particular attention to the structure of the cinchonized parasites. At about the same time independently, Romanowsky took up a similar line of work, employing his own staining method. Baccelli, Golgi, Marchiafava, and Bignami followed. The uniform result of all these investigations showed that the administration of quinin killed the parasites.
"Moreover, we will see that the changes manifested by the malarial parasites poisoned by quinin are strikingly similar to the changes described by Binz and his pupils (1867) in infusoria:
"Looking first at the quartan and common tertian parasites we find the following: In the ameboid forms of the tertian parasite three hours after the administration of 0.5 to 1.0 quinin, a decided diminution of the ameboid movement is found. After a further period of three to six hours the number of parasites is considerably decreased, and among those remaining many are broken up so as to form several little balls entirely unconnected with one another within the red blood corpuscle.
" In the adult forms of the tertian parasite we observe either a complete cessation of the pigment movement when the organism shows a glistening, homogeneous appearance, as if coagulated, or a dropsical enlargement of the parasite, associated with lively oscillatory movement of the pigment, or, finally, a breaking up of the parasite into several fragments, similar to that occurring in the young endoglobular forms.
" The last two appearances, namely, the breaking up of the parasites and the dropsical swelling, may occur during the paroxysm, apart from the action of quinin, and though the former signifies undoubted death, the dropsical swelling is perhaps only a sort of check to development, or, rather, to reproduction; in other words, the making of the parasite sterile.*
"Further, a short time after the administration of quinin medium sized tertian parasites are often observed in very active, so to speak convulsive, movement. We have seen a somewhat similar condition during the fever paroxysm. It would appear, therefore, as if the parasites are at first irritated to increased movement. Binz described the same among the infusoria.
* Herbst found, in 1867, that quinin in dilute solution checked the reproductive power of the infusoria. Death resulted on stronger concentration.
" If the quinin has been exhibited in two or three doses of 0.5, four to six hours before the paroxysm, tertian parasites may sporulate normally or may be checked before reaching full development. We will return to these later when speaking of the structure of quinin forms.
"In the medium sized quartan parasites Golgi observed a less fine granulation, a metallic luster, and an inclination to shrinking. The large forms were swollen, showed lively oscillatory movement of the pigment, and sometimes contained vacuoles or abortive spores.