The amount of the tannin runs extremely small, any addition of which can be readily detected. One-fourth of the ash of cinnamon is soluble in water, but less of “Cassia Vera,” and less yet of cassia lignea. Little has been learned which would form a sound basis for distinguishing these barks. The presence of manganese cannot be considered as indicating that substance an essential element of the ash, nor is the fact one from which such definite conclusions could be drawn as to serve as the basis of legal testimony, but it is what gives to the different barks their different colors. True cinnamon contains less than 1 per cent. of oxide of manganese; “Cassia Vera” more than 1 per cent., and cassia lignea as high as 5 per cent.

The essential oil is but 0.5 to 1 per cent. of the bark of cinnamon and much less in inferior cassia.

We also find the presence of mucilage, coloring matter, resin, acid, starch, and lignea as well as volatile oil. Aside from the determination of volatile oil upon which the properties of cassia bark depends, chemical analysis seems to be of little value; the principal dependence must, with our present knowledge, be placed on the mechanical and microscopic examination.

To detect the adulteration of oil of cassia by oil of cloves, a drop of the oil should be heated on a watch glass. Genuine cassia evolves a fragrant vapor possessing but a little acridity. When, however, clove oil is present, the vapor is very acrid and excites coughing. With fuming nitric acid, cassia merely crystallizes; but if cloves be present it swells up, evolves a large quantity of red vapor and yields a thick reddish-brown oil. Pure cassia oil solidifies with concentrated potash but will not when mixed with clove oil.

A good test for cassia oil substituted for oil of cinnamon is to add nitric acid, specific gravity 1.36, to oil of cinnamon (one part of the latter to two parts of acid), and shake the mixture. A bright orange-colored liquid is first obtained, upon the surface of which floats an orange, resinous substance, slowly becoming deeper in color, until a beautiful cherry-red color is visible, by which time it has changed to a liquid that floats on a lighter-colored substratum, which also in a short time becomes nearly of the same tint. Bubbles then commence to appear and shortly afterwards spontaneous ebullition occurs, with the evolution of nitrous fumes and vapors of benzoic aldehyde. By the time this ebullition has ceased the amber-colored liquid commences to clear itself and finally a clear amber liquid is left with orange globules floating on its surface. Upon oil of cassia, nitric acid, specific gravity 1.36, has a different action, as, after mixing one part of oil of cassia with two of nitric acid, a dirty green supernatant resinous mass (slowly turning brown) is seen floating on a yellowish liquid, and no further change takes place. If a large excess of the acid be added after the first addition, the resinous mass changes to a deep reddish brown and the subnascent liquid takes a cherry-red color. The same reaction occurs if a large excess of nitric acid be added to oil of cassia at first, but in neither of these cases is there any spontaneous ebullition or evolution of the nitrous fumes and benzoic aldehyde vapors.

If oil of cassia be mixed with oil of cinnamon, the reaction with nitric acid takes place as with oil of cinnamon, but more tardily, according to the amount of cassia oil present; and, at the end of the process, a turbid subnascent liquid is seen, instead of a clear one, as is the case with pure oil of cinnamon. Spirits of nitrous ether can also be used to distinguish between these oils, as it forms a clear solution with that of cinnamon, but a turbid one with cassia.

CHEMICAL COMPOSITION OF CASSIA AND CINNAMON

Samples examined, ash of the whole being about 8 per cent. and powdered 5 per cent.:

Ash Saigon,8.23
Unknown Cassia,1.75, extreme
Fiber Saigon,26.29
Fiber of Cassia Cinnamon,14 to 20, extreme
Fiber True Cinnamon,33.08
Albuminoids Saigon,4.55
Albuminoids Unknown Cassia,2.45, extreme
Lime True Cinnamon,40.09, 36.98, 40.39, in three specimens
Lime Cassia Lignea,25.29
Lime “Cassia Vera,”52.72
Magnesia, True Cinnamon,2.65, 3.30, 3.86, in three specimens
Magnesia, Cassia Lignea,5.48
Magnesia, “Cassia Vera,”1.10