7. Lichenes peltati.
Such as consist of a tough or coriaceous matter, disposed into a foliaceous appearance; on the edges of which, in general, the parts of fructification are placed, in the form of flattish oblong bodies, in these mosses called shields or pelts.
This division contains the third series of the second order of Dillenius’s lichenoides; the lichenes coriacei of Linnæus; and several of the placodium of Hill.
That celebrated and well-known plant, the ash-coloured ground liverwort[117] of Ray belongs to this order. It is very common all over England on dry and barren ground; and indeed almost all Europe, and America too, seems to afford it in sufficient plenty, as we find it observed by almost all the botanic writers since Ray, who was one of the first that described it.
The earliest account we have of its use for the bite of a mad dog is in the Philosophical Transactions[118], from Mr. Dampier, in whose family it had been a secret for a number of years. It was communicated first to Sir Hans Sloane, as a kind of fungus, or Jew’s-ear; and, at the request of Dr. Mead, was some years afterwards received into the London dispensatory. Scarce any of the boasted specifics of former ages ever acquired so great reputation as this plant has done in modern times, for its prevalence against the bite of a mad dog; and the patronage of the late learned Dr. Mead made it sufficiently known throughout all the world. Happy would it be indeed, if it fully deserved the high encomiums, which have been bestowed upon it. A great and eminent physician[119] has doubted its efficacy at all in such cases; and it is well known, that Boerhaave even laughed at it. Dr. Mead had certainly an high opinion of it: he tells us it never failed, thro’ the course of thirty years experience, where it was duly given before the hydrophobia came on[120]. Later instances have shewn, that it is not infallible; and Dr. Van Swieten’s supposition is but too likely to prove true. It must be confessed, that Dr. Mead’s exhibition of it seems too much complicated with other means to leave room for judging fully of its real efficacy; and it may really be questioned, whether bleeding, pepper, and cold-bathing, have not had more to do in the case than the lichen.
The muscus pulmonarius officinarum[121], tree-lungwort, or oak-lungs, belongs to this order. It is found about old oaks, and upon rocks and stones overgrown with moss, in many of our thick woods in England; but not in any great plenty.
Few, perhaps, of the antiquated simples were in more repute, in their day, than this plant. It was celebrated for ages, on account of its supposed prevalence in pulmonary complaints of almost all kinds; and yet, upon inquiry into the original of its use in such cases, it would probably appear, that it arose more from a fansied resemblance they found in the plant to the lungs themselves, than from any real and well-grounded proofs of its efficacy. As a gentle astringent, like most other species of the family, it would doubtless contribute to relieve in many cases where the lungs were affected, as in hæmoptoës, and some others: but it does not seem, by any means, to deserve that high character in medicine which has been given to it.
The people in Herefordshire, where this moss is called rags, dye their stockings of a brown colour with it. This is done by a very strong but simple decoction in water, and the colour stands well[122].
The fine green lichenoides with black warts[123], is a celebrated medicine, and in very frequent use, with the country people about Upsal, for the thrush in children: to this end they give an infusion of it in milk. A medicine of this kind is of great importance in those countries, where that disorder occurs much more frequently than with us[124]. It is not received into the Swedish dispensatory; but is known however in the shops, under the name of muscus cumatilis. We have it not in England; and Dillenius found it but in one place about Geissen: in the woods of Sweden it is more plentiful. A singular case, which is related in the Amænitates Academicæ[125], has given rise to an opinion of its usefulness in the worms also. The case briefly was this: A country girl had, for near half a year, complained of excruciating pains in her stomach and bowels, which were attended with vomiting, anxiety, and great watchfulness. All that had been prescribed for her by Professor Linnæus and others, who took her case for the worms, proved altogether fruitless. Being afterwards left to the care of her neighbours and relations, some good women gave her a decoction of this moss, which the Uplanders call elfnefwer. After she had taken it a few days, she vomited up six or seven roundish worms, and was cured. These were found, upon examination, to be the maggots of a kind of brown bee-fly, described by Mr. Ray[126], and by Linnæus[127].
However insufficient this history may be, to prove the usefulness of this plant as a vermifuge, it will at least serve to exemplify this fact; namely, that other animals of the insect kind, besides the teniæ, lumbrici, and ascarides, may subsist a long time in the primæ viæ of the human body, and be the cause of great disturbances therein[128].
Necessity is frequently the parent of the most useful and important discoveries: and the uses to which a plant of this order is appropriated by the natives of Iceland, is a standing proof of the truth of this observation. That climate will scarcely permit the cultivation of any kind of grain; but the want of it is in a great measure happily supplied by the eryngo-leaved lichenoides[129], which is abundant in the northern regions; and in that island particularly the natives have long been acquainted with the methods of applying it both to the purposes of food and of physic.
Ray has long since informed us[130], from Bartholine, that in the spring time, while it is young, it will purge; in consequence of which it is used as common spring physic. This quality it loses in a short time; and what serves for physic in the spring, is converted the remaining part of the year into food. They collect large quantities of it, grind it into meal, and make both pottage and bread of it. It is in common use not only with the islanders, but in several parts of Sweden also, where it is found to be a very appropriate diet in phthisical cases[131]. These accounts of the excellent use of this lichen correspond perfectly well with the last accounts of it in Mr. Horrebow’s Natural History of Iceland, just published; and which I shall take the liberty of transcribing as follows: “There is another herb, called muscus catharticus islandiæ, or mountain-grass, which they cook up into a delicate dish. I have often eat of it; at first out of curiosity, but afterwards for its palateableness and wholesomeness. The excellent qualities of this herb are described in the Memoires of the Society of Arts and Sciences in Sweden. It grows in great abundance; and those that live near the places, where it is found, gather great quantities for their own use, and to send to market. People that live at a great distance will send and fetch horse-loads away. Many use no meal or flour at all, when they are stocked with this herb, which in every respect is good and wholesome food”[132].
This moss is not very common in the southern countries of Europe. England affords it but very sparingly. Mr. Newton and Dr. Dillenius found it in Wales; Sibbald, in Scotland. It is frequent on the Alps of Switzerland; and Dr. Haller mentions it in his Iter Hercynium. Sweden and Lapland have it in plenty: and on account of its great abundance and usefulness in Iceland, Bartholine, and after him others, called it muscus islandicus.