Part II.

Materia Medica.

IIS

jelly contracting and separating from the fluid, as curd doesfrom whey.

Medical use __From the analysis of this lichen, it appears

to consist principally of a nutritious substance, combined witha bitter; and on the combination of these, its medical virtuesprobably depend. It is used, according to Arnemann,

!. In cough with expectoration, threatening to terminatein consumption; after neglected catarrhs, the conse-quence of peripneumony, when the expectoration be-comes more copious and purulent.2. In emaciation from measles, (Schoenheide) ; fromwounds and ulcers with great discharge, (Plenk); af-ter salivation ; and from actual ulcers in the lungs,when there is no fever, (Scopoli), especially after ne-glected colds, or from translated morbid matter. In ahigh degree of the disease it does little good, but thenight sweats are diminished by it, (Millin). In pitui-tous phthisis it is of great service.

4. In haemoptysis, (Frize).

5. In chincough, (Tode).

6. In diabetes, as a tonic and palliative remedy.

It is commonly exhibited in decoction with water, broth, ormilk, after the bitter has been extracted from it by steeping itin warm water; or in substance, boiled in chocolate or cocoa,or made into a jelly with boiling water. Half an ounce, oran ounce, must be used daily, and continued for some time.Proust disbelieves its specific virtues, but recommends itstrongly as an article of diet in times of scarcity, and as a veryconvenient antiscorbutic vegetable in long sea voyages.

Sj>. 115. Lichen rocella. Dud.Orchill.

Off". —Litmus, turnsole.

Litmus, lacmus tinctorius. Dub.

This lichen is found in Guernsey and Portland island, butit is from the Canary islands that it is chiefly obtained. It isnot sold in the state of the plant merely dried, but manufactu-red by the Dutch into a paste, called Litmus, Qrseille en pate.It is sold in square masses, about an inch in length, and halfan inch in breadth and thickness, hard and brittle, having theappearance of a violet-coloured earth, with white spots. Ithas a violet smell, probably from the addition of oris rootpowder; and when tasted, speedily tinges the saliva, and givesa sense of heat in the mouth. This paste is prepared by mak-ing the lichen undergo a kind of fermentation in vats with