Cassia bark ([Fig. 3]), French cassia and German cassia, are the dried bark of a tree which grows twenty to forty feet high, sometimes even sixty feet high, irregular and knotty, with large spreading horizontal branches, outer bark thick, rough and scabrous, with ash color, speckled inner bark reddish with dark green and light orange color. It is known to commerce as cassia lignea or China cinnamon, and is from the Cinnamomum aromaticum. It is found in South China and is a native of Ceylon, Cochin China, East India, and Java, and has been brought from China since the earliest days of history. It is produced by an undescribed tree of several species of cinnamomum, differing from each other in foliage and in inflorescence and aromatic properties, and has about as many names in Chinese as there are provinces in which it is found growing. It is found most abundantly in the province of Kwangsi in the south of China, large quantities being brought to Canton annually from “Kwei lin Foo” (literally the City of the Forest of Cassia Trees), deriving its name from the forests of cassia around it, and is the capital and principal city of the province. The exact botanical source of China Cassia lignea was not known until 1884, although it was generally attributed to the tree now proved to yield it (Cinnamomum cassia). It is cultivated in the three following districts of China: Taiwu, Kwangsi province, and Lukpo and Loting, both in Kwang-tung province. Taiwu is about 180 miles west of Canton and from four to five miles from the West River, but the nearest cassia plantations are from twenty-five to thirty miles farther, in a southern or southwestern direction. The Loting district commences from eight to ten miles from Loting City. After leaving the West River about eighty miles of the Loting River and the Nam-Kong must be traversed before reaching the city, and from there the distance is made overland. In these plantations there are 52,600 acres which have been under cultivation for about forty years. Lukpo is least important. The city of Lukpo is situated on the northern bank of the West River. The nearest plantation is about fifteen miles distant from Lukpo City.
Cassia is also found in the following provinces: Hunan, Shensi, Hupeh, and Eonsu, and under the following Chinese names: Yuk-quai-she, Toro-Tsao, Chu-eh or Tsao, Chu-eh, Eh-Ming or Chueh Mings; for drugs—fungus, Huei-hua, Mu-erh. The Chinese have varieties which they cultivate under special circumstances, almost sacred, and by their long familiarity with different kinds and their expertness in determining its value they use it in many ways of which we are ignorant. The thick bark of the old uncultivated trees found growing near the Annam frontier is very highly valued by the Chinese on account of its supposed medicinal purposes, especially a dark bark called Ching Fa Kwei from the trees growing on the Ching Fa Mountains in Annam. The bark is stripped from the limbs as are the other grades of cinnamon. It is only about sixteen inches in length, has a dark-brown color and dull flavor, is not so sweet as true cinnamon and has a bitter taste. The bark is thick and heavy and not uniform in size. It is not enclosed or quilled and is brittle, with a less fibrous texture. It is less pungent and has a more mucilaginous or gelatinous quality. The outer, corky bark is of a deeper color and is the kind mixed with much coarser bark, known as “Cassia Vera,” which is ground by our spice grinders in place of the true cinnamon. This bark is imported in mats of from three to four pounds each, bound up in bamboo splints, and is shipped in bales of about eighty pounds.
Inferior cinnamon trees are found scattered over a large tract of country in the Indian Archipelago, C. Tamala Nees, and Eberm, extending into Silhet, Sikkin, Nepaul, Kumaon, and even into Australia. There are two species of Archipelago C., Cassia Blume and C. Burmanii Blume, the last being a Chinese variety found growing in Sumatra and Java, and the Philippines furnish “Cassia Vera.” Several other cassia Cingalese species of cinnamon cassia bark are found in their respective localities.
In the Khasia Mountains of East Bengal there is the bark of Abtusifolium Nees, and C. Pauciflorum Nees, and C. Tamala Nees, and Eberm found growing at 1,000 to 4,000 feet elevations, shipped from Calcutta. Cinnamomum iners reinw is a kind found in India, Ceylon, Java, and Sumatra, and other islands in a variable state and has a paler and thinner and different veined leaf than the true cinnamon. Young branches of the tree are collected and tied up in fagots constituting cassia twigs, which form a large article of commerce.
In order to powder cinnamon bark, it must first be passed through a cracker machine, as it is called, to reduce it to a proper size for feeding in a mill. The mill consists of a roller provided with very coarse teeth, which revolve through similar stationary teeth. The material is retained by a semi-circular, perforated plate, until it is reduced to the size of the perforation, or about the size of a coffee bean, when it is then ready for the burr stones.
True ground cinnamon (see [Figs. 22 and 23], Chap. III) consists of long cells of woody fiber which represent the thin layers found in the bark and scattered through it, consisting of a little starch in stellate cells. There is nothing more distinct between cinnamon and cassia than the amount of volatile oil the bark contains, and yet some of the inferior cinnamon bark does not contain as much volatile oil as does good cassia, but cinnamon oil is of a much higher and more delicate aroma. It is hard to detect cassia (see [Fig. 41], Chap. III; adulterated, [Fig. 46]) in ground cinnamon, as the flavor is so similar, but the cassia contains but little wood fiber and few stellate cells and the presence of starch is more marked. To test cinnamon, experts are required. The usual test is by chewing, but this method soon makes the mouth sore. The most inferior ground cassia, however, bears such a close resemblance to the best cassia and to the true cinnamon that it may be substituted for it or used as an adulterant without being easily detected. The following instructions are useful in examining powdered cinnamon.
Make a decoction of pure ground cinnamon, also a decoction of the suspected mixture, and filter both; when cold add to thirty grams of each one or two drops of iodine, when the decoction of pure cinnamon will be but slightly affected while the mixture will assume a blackish-blue coloration. Although much depends upon the age of the oils, the greater the age of the oil the smaller the quantity of iodine solution absorbed by it. The cheap sort of cassia, or “Cassia Vera,” can be distinguished from China cassia and from true cinnamon by its richness in mucilage, which can be extracted by cold water as a thick glary liquid, which on the addition of corrosive sublimate or neutral acetate of lead yields a dense viscous precipitate. The most reliable test for cassia in true cinnamon is to obtain the proportion of ash in each, the ash in cinnamon being 4.59 and 4.78 per cent., cassia lignea giving but 1.84 and “Cassia Vera” nearly the same as cinnamon, 4.08. Another test is to ascertain the amount of ash soluble in water. The quantities are 25.04, 28.98 per cent. in whole cinnamon, about 18 per cent. in chips, and 8.15 in “Cassia Vera,” and 26.40 in cassia lignea. Again the proportion of oxide of manganese is never more than 1 per cent. (0.13-0.97) in cinnamon, but it is over (1.13-1.53) in “Cassia Vera” and 3.65-5.11 in cassia lignea. The cinnamon ash will always be found white or nearly so, while both the cassia ashes are gray or brown and yield an abundance of chlorine on heating with hydrochloric acid. The cinnamon or cassia in the bark is easily distinguished, as the inferior kinds are thicker and appearance coarser and their color darker brown and duller and have a more pungent taste, which is less sweet than the true cinnamon, succeeded by a bitter taste.
The Ceylon bark is characterized by being cut obliquely at the bottom of the quill while other kinds are cut transversely. Ground cinnamon will deteriorate very rapidly. Cinnamon is so singularly sensitive in the bark that great care has to be taken in regard to its surroundings in shipping aboard vessels to prevent loss. Recourse has been made to various expedients, but it is found that the only effective safeguard is to pack bags of pepper between the bales. Ceylon alone exports 6,000 pounds of bark to this country annually in gunny bags of about 100 pounds each. Colombo (see [illustration]), which has one of the largest botanical gardens and the largest cinnamon grove in the world, is the principal city of export.
Cassia Buds (flores cassiæ immature clavelli cinnamomi) are the calyces of the immature flowers of the cassia tree which yields cassia lignea. The cassia buds of commerce bear a resemblance to cloves but are smaller and have the odor and flavor of cassia lignea or cinnamon. They are gathered in an unripe state at about one-fourth their normal size and are exported from Canton in piculs of 150 pounds each. Canton exported about 100,000 pounds in the first quarter of 1905, and Canton exports 19,000 piculs of cassia cinnamon of 133 pounds each and 500 piculs of twigs annually, and it is the principal city of export in the world for cassia barks. In Southern India the cassia buds are gathered from a variety of wild Cinnamomum iners reinw in a mature state, but they are inferior to the Chinese cassia buds. They have the appearance of nails with roundish heads of various sizes, and if completely dried the receptacle is nearly dark, firmly embracing the embryo seed, which protrudes.
Seeds which are used for seeding are obtained from trees ten years old and upward, which are not cut back but are allowed to grow naturally from fifty to sixty feet apart, while the balance of the orchard is cut down every six years for the bark. The seed trees are cut only in cases of necessity to supply a great demand for the thick bark on the trunks, when some can be sacrificed.