BLADDERWRACK 215 



hydrolysis galactose, dextrose, and levulose (Sebor, 1900), and also 

 hydroxymethylfurfuraldehyde (Mlither and Tollens, 1904), and 

 probably consists of galactan with glucosan and levulosan. The 

 drug yields from 8 to 18 per cent, of ash, in which a little iodine can 

 be detected, and about 7 per cent, of proteids. 



Uses. Irish moss possesses demulcent properties. It has been 

 given in pulmonary complaints and for chronic diarrhoea, and has been 

 used for the preparation of a nutritious jelly. It is also employed for 

 various technical purposes, such as calico dressing, &c., as a cheap 

 substitute for gum arabic. 



Varieties, &C. Oigartina mamillosa, J. G. Agardh, which is occasion- 

 ally found mixed with Irish moss, may be distinguished by its stalked 

 sporocarps, as may also Gigartina pistillata, Lamouroux, but the latter 

 is a rare British seaweed and its presence would indicate that the drug 

 had probably been collected in France ; the sporocarps of Chondrus 

 crispus are immersed in the thallus, the surface of which is slightly 

 raised over them. 



BLADDERWRACK 



(Fucus vesiculosus) 



Source, &c. Bladderwrack, Fucus vesiculosus, Linne (Class, Algce ; 

 Subclass, Phceophycece ; Order, Fucacece), is a seaweed widely dis- 

 tributed on the shores of the Atlantic Ocean, and one of the com- 

 monest seaweeds on the coast of Great Britain, growing on the rocks 

 and stones exposed at low tide. For medicinal use, the entire living 

 plant should be collected and dried. That which is thrown up by 

 the sea should be rejected, as by contact with the sea water it is liable 

 to lose some of its constituents, which easily diffuse out from those 

 cells the protoplasm of which has lost its vitality. 



Description. Bladderwrack, when fresh, is of a dark olive brown 

 colour, changing, as the weed dries, to nearly black. The thallus of 

 the plant is thin and flattened, about 2 cm. wide and up to a metre 

 or more long. It has an entire margin, and branches dichotomously, 

 bearing at intervals bladder-like swellings (air-vesicles) arranged 

 mostly in pairs ; some of the branches terminate in club-like enlarge- 

 ments, in which the organs of reproduction are situated. When 

 slightly moist it is cartilaginous, but when quite dry, hard and brittle. 

 It has a peculiar seaweedy odour and a disagreeable, mawkish, 

 mucilaginous, and saline taste. 



The student should observe 



(a) The entire margin, 



(b) The vesicles usually in pairs. 



