Winter’s Bark has a short, almost earthy fracture, an intolerably pungent burning taste, and an odour which can only be described as terebinthinous. When fresh its smell may be more agreeable. The descriptions of Clusius, as alluded to above, are perfectly agreeing and even his figures as nearly as might be expected.
Microscopic Structure—In full-grown specimens the most striking fact is the predominance of sclerenchymatous cells. The tissue moreover contains numerous large oil-ducts, chiefly in the inner portion of the large medullary rays. A fibrous structure of the inner part of the bark is observable only in the youngest specimens.[83] Very small starch granules are met with in the drug, yet less numerous than in canella. The tissue of the former assumes a blackish blue colour on addition of perchloride of iron.
The wood of Drimys consists of dotted prosenchyme, traversed by medullary rays, the cells of which are punctuated and considerably larger than in Coniferæ.
Chemical Composition—No satisfactory chemical examination has been made of true Winter’s Bark. Its chief constituents, as already pointed out, are tannic matters and essential oil, probably also a resin. In a cold aqueous infusion, a considerable amount of mucilage is indicated by neutral acetate of lead. On addition of potash it yields a dark somewhat violet liquid. Canella alba is but little altered by the same treatment. By reason of its astringency the bark is used in Chili for tanning.[84]
Uses—Winter’s Bark is a stimulating tonic and antiscorbutic, now almost obsolete in Europe. It is much used in Brazil and other parts of South America as a remedy in diarrhœa and gastric debility.
Substitute—False Winter’s Bark—We have shown that the bark of Drimys or True Winter’s Bark has been confounded with the pungent bark of Canella alba L., and with an allied bark, also the produce of Jamaica. The latter is that of Cinnamodendron corticosum Miers,[85] a tree growing in the higher mountain woods of St. Thomas-in-the-Vale and St. John, but not observed in any other of the West Indian islands than Jamaica. It was probably vaguely known to Sloane when he described the “Wild Cinamon tree, commonly, but falsely, called Cortex Winteranus,” which, he says, has leaves resembling those of Lauro-cerasus; though the tree he figures is certainly Canella alba.[86] Long[87] in 1774, speaks of Wild Cinamon, Canella alba, or Bastard Cortex Winteranus, saying that it is used by most apothecaries instead of the true Cortex Winteranus.
It is probable that both writers really had in view Cinnamodendron, the bark of which has been known and used as Winter’s Bark, both in England and on the continent from an early period up to the present time.[88] It is the bark figured as Cortex Winteranus by Goebel and Kunze[89] and described by Mérat and De Lens,[90] Pereira, and other writers of repute. Guibourt indeed pointed out in 1850 its great dissimilarity to the bark of Drimys and questioned if it could be derived from that genus.
It is a strange fact that the tree should have been confounded with Canella alba L., differing from it as it does in the most obvious manner, not only in form of leaf, but in having the flowers axillary, whereas those of C. alba are terminal. Although Cinnamodendron corticosum is a tree sometimes as much as 90 feet high[91] and must have been well known in Jamaica for more than a century, yet it had no botanical name until 1858 when it was described by Miers[92] and referred to the small genus Cinnamodendron which is closely allied to Canella.
The bark of Cinnamodendron has the general structure of Canella alba. There is the same thin corky outer coat (which is not removed) dotted with round scars, the same form of quills and fracture. But the tint is different, being more or less of a ferruginous brown. The inner surface which is a little more fibrous than in canella, varies in colour, being yellowish, brown, or of a deep chocolate. The bark is violently pungent but not bitter, and has a very agreeable cinnamon-like odour.
In microscopic structure it approaches very close to canella; yet the thick-walled cells of the latter exist to a much larger extent and are here seen to belong to the suberous tissue. The medullary rays are loaded with oxalate of calcium.