7.50 ALG^. 



frequently exhibits whitish globular or mammiform fruits (cystocarps). 

 It is somewhat friable, and after drying at 100° C. may easily be pow- 

 dered. It is devoid of taste and smell, in this respect differing from 

 most sea weeds. 



4 



Microscopic Structure — The transverse section shows a loose 

 tissue made up of large empty cells, enclosed by a cortical zone 30 to 

 70 mkm. thick. This zone consists of small cells, loaded with globular 

 starch-granules, from less than 1 up to 3 mkm. in diameter, so densely 

 packed as to form what seems at first sight a single mass in each cell 

 In the larger cells the granules are attached to the walls ; they do not 

 display in polarized light the usual cross. The thick walls of the cells 

 show a stratified structure, especially after having been moistened with 

 chromic acid; on addition of a solution of iodine in an alkaline iodide, 

 they assume a deep brown, but the starch-granules, which also abound 

 in the cystocarps, display the usual blue tint. 



Chemical Composition — The drug, as examined by O'Shaugh- 

 nessy, yielded in 100 parts of vegetable jelly 54*'5, starch 15-0, ligneous 

 fibre (cellulose 1) IS'O, mucilage 4-0, inorganic salts 7'5. 



Cold water removes the mucilage, which, after due concentration, 

 may be precipitated by neutral acetate of lead. This mucilage, when 

 boiled for some time with nitric acid, produces oxalic acid and micro- 

 scopic crystals of mucic acid (beautifully seen by polarized light), soluble 

 in boiling water and precipitating on cooling. With one part of the 

 drug and 100 parts of boiling water a thick liquid is obtained which 

 afibrds transparent precipitates with neutral acetate of lead or alcohol, 

 in the same way as carrageen. With 50 parts of water, a transparent 

 tasteless jelly, devoid of viscosity, is produced; in common with the 

 mucilage, it furnishes mucic acid, if treated with nitric acid. Micro- 

 chemical tests do not manifest albuminous matter in this plant. 



Some chemists have regarded the jelly extracted by boiling water 

 as identical with pectin, but the fact requires proof. Payen' called it 

 Gelose, and found it composed of carbon 42*77, hydrogen o*77, and 

 oxygen 51-45 per cent. Gum Arabic contains carbon 4212, hydrogen 

 6-41, and oxygen 51-47 = C^'H'^O'^ Payen's gelose imparts a gelatinous 

 consistence to 500 parts of water ; it is extracted by boiling water from 

 the plant previously exhausted by cold water slightly acidulated.^ 



The inorganic salts of Ceylon moss consist, according to O'Shaugh- 

 nessy, of sulphates, phosphates, and chlorides of sodium and calcium, 

 with neither iodide nor bromide. Dried at 100° C, it yielded us 915 

 per cent of ash. 



Uses.— A decoction of Ceylon moss made palatable by sugar and 

 aromatics, has been recommended as a demulcent, and a light article of 

 food for invalids. In the Indian Archipelago and in China, immense 

 quantities of this and of some other species of seaweed ^ are used for 

 making jelly and for other purposes. 



^Cmipf^^s Rendus, xlix. (1859) 521; siats mainly of it, will keep good for years. 



Pharm Journ. i. (I860) 470. 508. 3 Consult Martins, NeuesJahrh.f. Pharm. 



Uelose even m the moist state is but Bd. ix. Mitrz 1858 : Cooke, Pharm. Journ. 



K\7+l^nw *^^^"S^' ^""^ ^^^ J^"y ^^^^« i- (I860) 504: Holmes, Pharm, Journ. ix. 

 by the Chmese as a sweetmeat which con- (1878) 45 



