Fig. 131. Parmelia saxatilis Ach. (S. H., Photo.).
Lichens among other plants in which any “signature” could be detected or imagined were therefore constantly prescribed: the long filaments of Usnea barbata were used to strengthen the hair; Lobaria pulmonaria, the true lung-wort, with its pitted reticulate surface ([Fig. 72]), was marked as a suitable remedy for lung troubles; Xanthoria parietina being a yellow lichen was supposed to cure jaundice, and Peltigera aphthosa, the thallus of which is dotted with small wart-like tubercles[1267], was recommended for children who suffered from the “thrush” eruption.
The doctrine reached the height of absurdity in the extravagant value set on a lichen found growing on human skulls, “Muscus cranii humani” or “Muscus ex cranio humano.” There are a number of lichens that grow indifferently on a variety of substances, and not infrequently on bones lying in the open. This skull lichen[1268], Parmelia saxatilis ([Fig. 131]) or some other, was supposed to be worth its weight in gold as a cure for epilepsy. Parkinson[1269] tells us in all confidence “it groweth upon the bare scalps of men and women that have lyen long ... in former times much accounted of because it is rare and hardly gotten, but in our own times much more set by, to make the ‘Unguentum Sympatheticum’ which cureth wounds without the local application of salves ... but as Crollius hath it, it should be taken from the sculls of those that have been hanged or executed for offences.” Ray[1270] says that the same gruesome plant “is celebrated by several authors as useful in haemorrhages and is said to be an ingredient of the famous ‘Unguentum Armarium[1271],’ reported to have been invented by Paracelsus.” Another lost ointment!
c. Cure for Hydrophobia. Still another lichen to which extraordinary virtue was ascribed, was the very common ground species Peltigera canina ([Fig. 54]), a preparation of which was used in the cure of rabies. Dillenius[1272] has published in full the prescription as “A certain Cure for the Bite of a Mad Dog” which was given to him by a very celebrated physician of that day, Dr Richard Mead, who had found it effective:
“Let the patient be blooded at the arm, nine or ten ounces. Take of the herb called in Latin Lichen cinereus terrestris, in English Ash-coloured ground liverwort, clean’d, dry’d and powder’d half an ounce. Of black pepper powder’d two drachms.
“Mix these well together and divide the Powder into four Doses, one of which must be taken every Morning, fasting, for four Mornings successively in half a Pint of Cow’s Milk warm. After these four Doses are taken, the Patient must go into the cold bath, or a cold Spring or River, every Morning fasting, for a Month. He must be dipt all over but not stay in (with his head above water) longer than half a minute, if the Water be very cold. After this he must go in three Times a Week for a Fortnight longer.”
Lightfoot[1273], some forty years later, refers to this medicine as “the once celebrated ‘Pulvis antilyssus,’ much recommended by the great Dr Mead.” He adds that “it is much to be lamented that the success of this medicine has not always answered the expectation. There are instances where the application has not prevented the Hydrophobia, and it is very uncertain whether it has been at all instrumental in keeping off that disorder.” Belief in the efficacy of the powder died out before the end of the century but the echo of the famous remedy remains in the name Peltigera canina, the dog lichen.
d. Popular Remedies. Lichens with very few exceptions are non-poisonous plants. They owed their repute as curative herbs to the presence in the thallus of lichenin and of some bitter or astringent substances, which, in various ailments, proved of real service to the patient, though they have now been discarded in favour of more effective drugs. Some of them, on account of their bitter taste, were frequently used as tonics to replace quinine in attacks of fever. Several species of Pertusaria, such as the bitter P. amara ([Fig. 132]), and of Cladonia as well as Cetraria islandica ([Fig. 128]), were recommended in cases of intermittent fever; species of Usnea and others, as for instance Evernia furfuracea, were used as astringents in haemorrhages; others were given for coughs, Cladonia pyxidata ([Fig. 69]) being supposed to be specially valuable in whooping cough.