CETRARIA 



7 a. FUNGUS CHIRURGORUM. Surgeon's 



See above. 



Agaric. Same as Polyporus. 



8. CEREVISL55 (Saccharomyces). FERMENTUM COMPRESSUM (Compressed Yeast), 



N.F. An organized ferment. Yeast is the name applied to the frothy scum 

 that forms on the surface of saccharine liquids and rises from the bungholes 

 of newly brewed beer. Under the microscope this froth is shown to consist of 

 particles which multiply with extraordinary rapidity when placed in a moder- 

 ately warm temperature. The globular forms are considered as the spores of 

 a fungus belonging to the genus Torula, the cells of which are but slightly 

 united, sometimes forming branching chains, the mycelium being almost ab- 

 sent. Yeast is employed in hastening the fermentation of worts and in leaven- 

 ing dough in bread-making. Bottom or sediment yeast is found on the bottom 

 of fermenting vessels. Two quite distinct methods of brewing are produced, 

 depending upon the employment of one or the other of these varieties of 

 yeast. For the purpose of the bakery, yeast is dried and formed into cakes. 

 Beer yeast is official in the B.P. Yeast, under the title of fermentum, 

 was official in the U.S.P., i82O-'4O, i86o-'8o, used as a tonic, laxative, 

 etc., but at present rarely employed. As a local remedy, as poultice, in 

 treatment of eruptions of boils, it still finds some favor. 



LICHENES 



Consisting mainly of a thallus (often leaf-like), without stem and leaves, 

 wholly cellular. Reproduced by spores. 



9. CETRARIA. ICELAND Moss. The entire plant, Cetra'ria islan'dica Acharius. 



Off. U. S. P. 1890. The crisp, leaf -like lobes are cartilaginous, whitish 



PIG. 7. Section of 

 thallus of Cetraria is- 

 landica through an 

 apothecium. as. Asci, 

 three of which contain 

 ascospores. gon. Gon- 

 idia. 



FIG. 8. Cetraria islandica. 



on the under surface, channeled and fringed at the margins. A strong decoc- 

 tion gelatinizes on cooling ; taste mucilaginous and bitter. The Pharmacopoeia 

 calls attention to the fact that the drug is frequently mixed with pine leaves, 

 moss, and other lichens; from these it should be freed. Constituents: It is 

 largely composed (70 per cent.) of lichen starch, lichenin, and isolichenin, a 



