Rose stearoptene is a very stable body, yet by boiling it for some days with fuming nitric acid, it is slowly dissolved, and converted into various acids of the homologous series of fatty acids, and into oxalic acid. Among the former, we detected butyric and valerianic. The chief product is however succinic acid, which we obtained in pure crystals, showing all the well-known reactions.
The same products are obtained even much easier by treating paraffin with nitric acid; it yields however less of succinic acid. The general behaviour and appearance of paraffin is in fact nearly the same as that of rose stearoptene. But what is called paraffin, is a series of extremely similar hydrocarbons, answering to the general formula CₙH₍₂ₙ₊₂₎ (n being equal to more than 16), the separation of which has not yet been thoroughly effected. The fusion point of the different kinds of paraffin generally ranges from 42 to 60° C., yet one sort from the bituminous shale of Autun, prepared and examined by Laurent,[1028] melts at 33° C., and in this respect agrees with our stearoptene. It is therefore possible that the latter actually belongs to the paraffin series.
We have not ascertained the correctness of Baur’s strange experiments (1872, Jahresbericht der Pharm. p. 460), by which he believes to have converted the liquid part of rose oil into the stearoptene by means of a current of hydrogen.
Commerce—Formerly attar of rose came into commerce by way of Austria; it is now shipped from Constantinople. From the interior, it is transported in flattened round tin bottles called kunkumas, holding from 1 to 10 lb., which are sewed up in white woollen cloth. These sometimes reach this country, but more commonly the attar is transferred at Constantinople to small white glass bottles, ornamented with gilding, imported from Germany.
Uses—Attar of rose is of no medicinal importance, but serves occasionally as a scent for ointments. Rose water is sometimes made with it, but is not so good as that distilled from the flowers. Attar is much used in perfumery, but still more in the scenting of snuff.
Adulteration—No drug is more subject than attar of rose to adulteration, which is principally effected by the addition of the volatile oil of an Indian grass, Andropogon Schœnanthus L. This oil, which is called in Turkish Idris yàghi, and also Entershah, and is more or less known to Europeans as Geranium Oil, is imported into Turkey for this express purpose, and even submitted to a sort of purification before being used.[1029] It was formerly added to the attar only in Constantinople, but now the mixing takes place at the seat of the manufacture. It is said that in many places the roses are absolutely sprinkled with it before being placed in the still. As grass oil does not solidify by cold, its admixture with rose oil renders the latter less disposed to crystallize. Hence arises a preference among the dealers in Turkey for attar of the mountain districts, which, having a good proportion of stearoptene, will bear the larger dilution with grass oil without its tendency to crystallize becoming suspiciously small. Thus, in the circular of a commercial house in Constantinople, dated from Kizanlik, occur the phrases—“Extra strong oil,”—“Good strong congealing oil,”—“Strong good freezing oil;”—while the 3rd quality of attar is spoken of as a “not congealing oil.” The same circular states the belief of the writers, that in the season in which they wrote, “not a single metical of unadulterated oil” would be sent away.
The chief criteria, according to Baur, for the purity of rose oil are:—1. Temperature at which crystallization takes place: a good oil should congeal well in five minutes at a temperature of 12·5° C. 2. Manner of crystallizing.—The crystals should be light, feathery, shining plates, filling the whole liquid. Spermaceti, which has been sometimes used to replace the stearoptene, is liable to settle down in a solid cake, and is easily recognizable. Furthermore, it melts at 50° C. and so do most varieties of paraffin. The microscopic crystals of the latter are somewhat similar to those of rose stearoptene, yet they may be distinguished by an attentive comparative examination.
FRUCTUS ROSÆ CANINÆ.
Cynosbata; Fruit of the Dog-rose, Hips; F. Fruits de Cynorrhodon; G. Hagebutten.
Botanical Origin—Rosa canina L., a bush often 10 to 12 feet high, found in hedges and thickets throughout Europe except Lapland and Finland, and reaching the Canary Islands, Northern Africa, Persia and Siberia; universally dispersed throughout the British Islands.[1030]