Cooley's Cyclopaedia of Practical Receipts Volume I Part 148

The method followed in the collection of the bark by the Peruvians is a very wasteful and destructive one, and consists either in stripping the bark from the trees when they have attained a sufficient age, or in felling the tree a little above the roots. If the latter method be adopted, the roots give out a growth of suckers, which yield a good bark.

The bark is never removed during the rainy season.

Previous to being stripped off, the bark is sometimes cleaned with a brush, and then peeled off in pieces varying from 15 to 18 inches long, and from 4 or 5 in width. The thinnest pieces, which are derived from the branches or the trunks of small trees, are dried in the sun, and thus acquire the well-known quill-like form. The larger trunks yield the flat specimens, which are submitted to a kind of pressure as they are being dried. The inferior specimens being rejected, the dried barks (mostly of the same kind) are sewed in canvas, and thus conveyed to the nearest depot, from whence, previous to being shipped, they are enclosed in another envelope of fresh hide, the package being then known under the name of a _seron_.

_Structure of Cinchona Barks._ A few general observations on the structure of the bark of cinchona will be appropriate here. The epidermis is only found on the youngest bark, before it has attained sufficient age for medicinal use; it is then replaced by the corky layer. In most species this cracks, and is easily separable, but in some it is firmly attached to the internal layers. These are composed of the middle layer of the bark or mesophlaeum, formed of parenchyma, and the innermost layer endophlaeum, or liber. The middle layer disappears in some barks, which are thus wholly composed of liber. This is a means of distinguishing them. The liber is traversed by medullary rays, which project into the mesophlaeum. It is, therefore, composed of woody fibres (prosenchyma) and soft parenchyma.

The arrangement of the woody fibres, their colour, size, and shape, give a special character to the cinchona barks.

As compared with other barks, the fibres of the liber are shorter and more loosely arranged, being for the most part separate or united into very short bundles. The fibres, therefore, are easily isolated; they are spindle-shaped, sub-quadrangular, rarely exceeding 1-10th of an inch in length, usually straight, and are very brittle, the cavity of the cell of which each is composed being reduced by secondary deposits to a fine ca.n.a.liculus. This short and loose fibrous structure is not found in other barks.

In some cinchona bark a system of lactiferous vessels is found between the liber and mesophlaeum.[247]

[Footnote 247: Royle.]

The parenchyma of the barks abounds in starch and oxalate of lime, or else contains a soft brown deposit.

The 'British Pharmacopia' divides the cinchona barks into the three cla.s.ses of--

1. YELLOW CINCHONA BARK. _Syn._ CINCHONae FLAVae CORTEX. The _Cinchona Calisaya_ of Weddell.

2. PALE CINCHONA BARK. _Syn._ CINCHONae PALLIDae CORTEX. The bark of _Cinchona officinalis_; var. _Condaminea_ of Hooker. This bark is also known under the name of _Crown-bark_, from its having formerly been used by the royal family of Spain.

3. RED CINCHONA BARK. _Syn._ CINCHONae RUBRae CORTEX. The _Cinchona succirubra_ of Pavon.

The therapeutic properties of the cinchona barks are due to the following alkaloids:--

Quinia, or quinine, having the composition C_{20}H_{24}N_{2}O_{2}.

Quinidia, or quinidine, having the composition C_{20}H_{24}N_{2}O_{2}.

Cinchonia, or cinchonine, having the composition C_{20}H_{24}N_{2}O.

Cinchonidia, or cinchonidine, having the composition C_{20}H_{24}N_{2}O.

Quinamina, or quinamine, having the composition C_{20}H_{24}N_{2}O_{2}.

Besides the above, an alkaloid, which has been named _Paracina_, has been obtained from the bark of the _Cinchona succirubra_; whilst in those barks which contain only small portions of the more active const.i.tuents above named there have been found two alkaloids, named respectively _Aricia_ and _Cusconia_, which have lately been accurately investigated by Hesse, who has determined their chemical const.i.tution (Liebig's 'Annalen und Berichte der Chemische Gesselschaft in Berlin').

_The following Prospectus of the princ.i.p.al Species of Cinchona is from_ FLuCKIGER and HANBURY'S '_Pharmacographia_,'

--------------------------------------+---------------------+-------------+--------------------+------------------------------------- Species (excluding Sub-species and Native Where Varieties) according to Weddell. Where figured. Country. cultivated. Product - Cinchona Barks.

--------------------------------------+---------------------+-------------+--------------------+------------------------------------- I. STIRPS CINCHONae OFFICINALIS-- 1. Cinchona officinalis, Hook. 'Bot. Mag.,' 5364 Ecuador Loxe, India, Ceylon, Java Loxa, or Crown Bark, Pale Bark.

2. " macrocalyx, Pav. Howard, 'N. Q.' Peru -- Ashy Crown Bark. The sub-species _C. Palton affords_ an important sort called _Palton Bark_, much used in the manufacture of quinine.

3. " luc.u.maefolia, Pav. " Ecuador, Peru -- Carthagena Bark, confounded with Palton Bark, but is not so good.

4. " lanciolata, R. and P. " Peru -- } Columbian Bark. Imported in immense } quant.i.ties for manufacture of 5. " lancifolia, Mutis. Karst., tab. 11, 12 New Granada India } quinine. The soft Columbian Bark } is produced by Howard's var.

} _oblonga_.

6. " amygdalifolia, Wedd. Wedd., tab. 6 Peru, Bolivia -- A poor bark, not now imported.

II. STIRPS CINCHONae RUGOSae-- 7. Cinchona Pityrensis, Wedd. Karst., tab. 22 (G). New Grenada, India Pitayo Bark. Very valuable; used by Triane Popayan makers of quinine. It is the chief source of quinidine.

8. " rugosa, Pav. Howard, 'N. Q.' Peru -- Bark unknown, probably valueless.

9. " Mutisii, Lamb. " Ecuador -- Bark, not in commerce, contains only aricine.

10. " hirsuta, R. and P. Wedd., tab. 21 Peru -- 11. " Carabayensis, Wedd. Wedd., tab. 19 Peru, Bolivia -- Bark, not collected.

12. " panudiana, How. Howard, 'N. Q.' Peru India, Java A poor bark, yet of handsome appearance; propagation of tree discontinued.

13. " asperfolia, Wedd. Wedd., tab. 20 Bolivia -- Bark not collected.

14. " umbelluliferae, Pav. Howard, 'N. Q.' Peru -- Bark not known as a distinct sort.

15. " glandulifera, R. and P. " Peru -- " "

16. " Humboldtiana, Lamb. " Peru -- False Loxa Bark, Jaen Bark. A very bad bark.

III. STIRPS CINCHONae MICRANTHae-- 17. Cinchona Australis, Wedd. Wedd., tab. 8 South Bolivia -- An inferior bark, mixed with Calisaya.

18. " scrobiculata, H. and B. " Peru -- Bark formerly known as _Red Cus...o...b..rk_ or _Santa Anna Bark_.

19. " Peruviana, How. Howard, 'N. Q.' Peru India } 20. " nitida, R. and P. " Peru India } Grey Bark, Huanuco, or Lima Bark.

21. " micrantha, R. and P. " Peru India } Chiefly consumed on the Continent.

IV. STIRPS CINCHONae CALISAYae-- 22. Cinchona Calisaya, Wedd. Wedd., tab. 9 Peru, Bolivia India, Ceylon, Java, Calisaya Bark, Bolivian Bark, Yellow Jamaica, Mexico Bark. The tree exists under many varieties; bark also very variable.

23. " elliptica, Wedd. " Peru, -- Carabaya Bark. Bark scarcely now Carabaya imported. _C. cuneura_, Miq.

(flower and fruit unknown), may perhaps be this species.

V. STIRPS CINCHONae OVATae-- 24. Cinchona purpurea, R. and P. Howard, 'N. Q.' Peru, Huamalies Bark, not now imported.

Huamalies 25. " rufinervis, Wedd. " Peru, Bolivia -- Bark a kind of light Calisaya.

26. " succirubra, Pav. -- Ecuador India, Ceylon, Java, Red Bark; largely cultivated in Jamaica British India.

27. " ovata, R. and P. " Peru, Bolivia India (?), Java (?). Inferior brown and grey barks.

28. " cordifolia, Mutis. Karst., tab. 8 New Granada, -- Columbian Bark (in part). Tree exists Peru under many varieties; bark of some used in manufacture of quinine.

29. " Tucujensis, Karst. Karst., tab. 9 Venezuela -- Maracaibo Bark.

30. " p.u.b.escens, Vahl. Wedd., tab. 16 Ecuador, -- Areca Bark (Cus...o...b..rk from var.

Peru, Bolivia _Pelletieriana_). Some of the varieties contain aricine. _C.

caloptera_, Miq., is probably a variety of the species.

31. " purpurascens, Wedd. Wedd., tab. 18 Bolivia -- Bark unknown in commerce.

The cinchona barks vary greatly in the amount of alkaloids they contain and in their proportion to each other, these being dependent upon the species or varieties, and many other circ.u.mstances. Of the alkaloids, quinia and cinchonia were till lately the most abundant, but since the introduction of cinchona cultivation into India, cinchonidia has been found in very large quant.i.ty. Royle says:--"Good Calisaya bark usually contains from 5 to 6 per cent. of quinia," but actually South American calisaya containing such an amount of quinia is rare in the market. Some barks, however, derived from cinchonas cultivated in India, such as _C.

Calisaya_, var. _Ledgeriana_, and some varieties of _C. officinalis_, yield even a still higher per-centage of quinine.

The South American crown, or loxa bark, is very variable, and contains chiefly cinchonia.

Red bark also varies considerably, yielding from 3 to 10 per cent. of alkaloids, of which quinia forms only a small fraction, whilst generally cinchonidia is predominant. The development of the alkaloids is greatly influenced by cultivation, but particularly by the "renewing process,"

which, applied to the _C. succirubra_, trebles the amount of quinine in the bark.

In addition to the alkaloids already mentioned, the cinchona barks contain the following acid principles:--KINIC ACID, CINCHO-TANNIC ACID, and QUINOVIC or CHINOVIC ACID. The quinovic acid is accompanied by an amorphous bitter substance, named CHINOVIN or QUINOVIA, which is present in much greater proportion than the acid, of which generally there are only traces. A description of these bodies will be found by referring to them under their respective names. CINCHONA-RED is another amorphous substance which is the body to which the red hue of the cinchona barks is due. It is produced when cincho-tannic acid is boiled with dilute sulphuric acid, sugar being formed at the same time.

When fused with potash, proto-catechinic acid is formed. Cinchona red dissolves sparingly in alcohol, freely in alkaline solutions, but neither in water nor ether. Thick red bark contains it to the amount of more than 10 per cent.

Cinchona red is the product of the oxidation of cincho-tannic acid, and is contained largely in South American red bark, because this is the product of old trees; but sparingly in Indian red bark, because this is always collected from trees not more than fourteen years old.

_Medicinal Properties of the Cinchona Barks._ The therapeutic effects of the cinchona barks are doubtless due to the alkaloids they contain; but spite of their variability of composition in this respect, which has been shown to be very great, they are very extensively employed in medical practice in the forms of powder, decoction, tincture, and extract.

Dr de Vrij, the eminent quinologist, is of opinion that the therapeutic effects of bark are chiefly due in part to the alkaloids, and in part to the cincho-tannic acid they contain; and as red Indian bark is rich in both these const.i.tuents, he considers it the best suited for medical practice. See QUINETUM.

Garrod says:--"Given in small doses, bark causes an increase of appet.i.te, especially in weak patients, and at the same time improves the condition of the muscular system; hence the improvement of the blood and general health. It may, therefore, be well designated a tonic.

Its power in bracing up the system is also seen in the check given to the colliquative sweating occurring in extreme debility. The pulse is not quickened by the use even of large doses of quinine, although it is frequently made stronger, nor does bark itself, in the majority of cases, increase the heart's action.

Bark also produces a peculiar influence upon the nervous system, which is exhibited in the extraordinary power it possesses of arresting the progress of certain diseases characterised by a periodical recurrence of their symptoms, as ague, the different forms of neuralgia, and certain inflammatory affections; how this effect is produced is at present unknown. Bark acts likewise as an astringent, and this property, combined with the tonic and antiperiodic powers, is often of much therapeutic value."