Of plants with a saponaceous juice, the ancients, at any rate, used one instead of soap; but it is difficult or rather impossible to define it. I shall not therefore content myself merely with transcribing the passages where it is mentioned, but I shall arrange whatever I can find respecting it in such a manner, as, according to my opinion, the names of plants ought to be explained in dictionaries.

Στρουθίον, Struthium, Latinis Herba lanaria, et Plinio etiam Radicula.

The above is all that the ancients have told us respecting this plant. The information is indeed very scanty, and at the same time it is not altogether certain; but even if it were, it would be sufficient only to confute some conjectures, but not to establish the systematic name of the plant. I call the properties of it described to us uncertain: first, because I do not know whether Pliny did not mean to distinguish the wild plant from that which was cultivated, and many have understood as alluding to the former that which I have applied to both: secondly, because the words of Theophrastus, being in one passage evidently corrupted, will admit of various constructions; and because in another, on account of some exceptions, of which he speaks, they appear at least to me unintelligible: thirdly, because Pliny, who gives us the best account of it, is the only author who calls the struthium or soap-plant radicula, a name by which is rather to be understood a dye-plant of the same kind as madder. We have reason therefore to suspect that he has confounded the properties of the two plants, especially as the fourth property was ascribed by others to a Rubia, Asperula, or Galium, which was cultivated in Syria, and named often radicula Syriaca. On the other hand, this diminutive is very ill-suited to a root which Pliny himself calls large.

The words of that author, “tingenti, quicquid sit cum quo decoquatur,” have been by some explained as if he meant that the struthium was a dye-plant, though as a soapy plant it must have been destitute of colour; and they have hence deduced a proof that Pliny confounded the struthium with the radicula used in dyeing. On the other hand, Hardouin reads unguentis instead of tingenti. He assures us that he found the former in manuscripts, and is of opinion that the sap of the struthium was used also for ointments.

In my opinion, however, tingenti must be retained; and the meaning is that when cloth was to be dyed it was necessary to prepare it for that purpose by soaking it and washing it with the sap of this plant. This he expressly tells us himself; “tingentibus et radicula lanas præparat.” It is probable that the ancient dyers mixed their dye-liquors with the juice of the struthium, for the same purpose as bran and the seeds of fenugreek are added to dye-liquors at present; that is, to render them thicker and more slimy, in order that the colouring particles may be longer and more equally suspended in or diffused through them[254]. The words quidquid sit cum quo decoquatur will now become intelligible. Whatever may be employed for dyeing, says the author, the addition of the juice of the struthium is serviceable.

As what has been said contains nothing that can enable us to determine the genus of the struthium according to the rules of botany, we may be allowed to conjecture that it was one of those plants still used for the like purpose in Italy and other neighbouring countries. Fuchs thinks it must have been the Saponaria officinalis (soap-wort), the roots of which indeed contain a saponaceous juice that readily changes the saliva into froth. The root was employed for that purpose by the impostor in Lucian; and the juice is used at present for cleaning wool and cloth. In the Helvetian Alps, the sheep, before they are shorn, are washed with a decoction of the plant and its roots; and with a mixture of ashes it serves for cleaning linen. The taste of it is so sharp, that it is compared by some to that of the small burnet-saxifrage.

This Saponaria officinalis however differs too much from the remaining properties[255] of the struthium. Its root is as thick only as a quill, or at most as one’s finger. The stem, which is three feet in height, throws out many branches, and cannot be called caulis ferulaceus, tenuis. It is not rough and prickly, and, instead of growing in poor rocky soil, it is rather fond of deep ground and the borders of corn-fields.