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.