Chærophyllum Anthriscus L. (Anthriscus vulgaris Pers.) and two or three other species of Chærophyllum have the lower leaves not unlike those of hemlock, but they are pubescent or ciliated. The fruits too are linear-oblong, and thus very dissimilar from those of Conium.
The latter plant is in fact clearly distinguished by its smooth spotted stem, the character of its involucral bracts and fruit, and finally by the circumstance that when triturated with a few drops of solution of caustic alkali, it evolves conine (and ammonia), easily observable as a white fume when a rod moistened with strong acetic acid is held over the mortar.
FRUCTUS AJOWAN.
Semen Ajavæ vel Ajouain; Ajowan, True Bishop’s weed.
Botanical Origin—Carum Ajowan Bentham et Hooker (Ammi copticum L. Ptychotis coptica et Pt. Ajowan DC.)—an erect annual herb, cultivated in Egypt and Persia, and especially in India where it is well known as Ajvan or Omam.
History—The minute spicy fruits of the above-named plant have been used in India from a remote period, as we may infer from their being mentioned in Sanskrit writings, as, for instance, by the grammarian Pānini, in the third century b.c. (or later?), and in Susruta.
Owing to their having been confounded with some other very small umbelliferous fruits, it is difficult to trace them precisely in many of the older writers on materia medica. It is however probable that they are the Ammi which Anguillara[1154] met with in 1549 at Venice, where it had then, exceptionally, been imported in small quantity from Alexandria. It is also, we suppose, the Ammi perpusillum of Lobel (1571), in whose time the drug was likewise imported from Egypt, as well as the Ammi alterum parvum, the seed of which Dodonæus (1583) mentions as being “minutissimum, acre et fervidum.” Dale,[1155] who says it is brought from Alexandria, reports it as very scarce in the London shops. Under the name of Ajave Seeds, the drug was again brought into notice in 1773 by Percival,[1156] who received a small quantity of it from Malabar as a remedy for colic; and still more recently, it has been favourably spoken of by Fleming, Ainslie, Roxburgh, O’Shaughnessy, Waring and other writers who have treated of Indian materia medica.
Description—Ajowan fruits, like those of other cultivated Umbelliferæ, vary somewhat in size and form. The largest kind much resemble those of parsley, being of about the same shape and weight. The length of the large fruits is about ⅒, of the smaller form scarcely ¹/₁₆ of an inch. The fruits are greyish brown, plump, very rough on the surface, owing to numerous minute tubercles (fructus muriculatus). Each mericarp has five prominent ridges, the intervening channels being dark brown, with a single vitta in each. The commissural side bears two vittæ. The fruits when rubbed exhale a strong odour of thyme (Thymus vulgaris L.), and have a biting aromatic taste.
Microscopic Structure—The oil-ducts of ajowan are very large, often attaining a diameter of 200 mkm. The ridges contain numerous spiral vessels; the blunt tubercles of the epidermis are of the same structure as those in anise, but comparatively larger and not pointed. The tissue of the albumen exhibits numerous crystalloid granules of albuminous matter (aleuron), distinctly observable in polarized light.
Chemical Composition—The fruits on an average afford from 4 to 4·5 per cent. of an agreeable aromatic, volatile oil; at the same time there often collects on the surface of the distilled water a crystalline substance, which is prepared at Oojein and elsewhere in Central India, by exposing the oil to spontaneous evaporation at a low temperature. This stearoptene, sold in the shops of Poona and other places of the Deccan, under the name of Ajwain-ka-phul, i.e. flowers of ajwain, was showed by Stenhouse (1855) and by Haines (1856) to be identical with