COTTON 431 



mucilage, to which their medical properties are due. They also yield 

 from 10 to 15 per cent of ash. 



MALV^E FOLIA. Mallow Leaves. The dried leaves of Malva 

 sylvestris and Malva neglecta (Fam. Malvaceae). 



Description. Leaves long petiolate, orbicular or reniform, slightly 

 truncate or cordate at the base, 10 to 20 cm. in length, 15 to 20 cm. 

 in width, with three to seven shallow, angular or rounded lobes, vena- 

 tion palmate, margins crenate-dentate, pubescent on both sides; 

 inodorous; taste very mucilaginous. 



Inner Structure. Epidermal cells mucilaginous, stomata, on both 

 surfaces, each with three or four neighboring cells; hairs of three dis- 

 tinct types; (a), small, short stalked glandular hairs; (6), large one- 

 celled curved hairs with thick walls and (c) stellate hairs having two 

 to six cells (the latter especially numerous in M. sylvestris) ; palisade 

 tissue of one or two rows of cells, the mesophyl of three or four rows; 

 calcium oxalate in rosette aggregates; mucilage cells numerous. 



Powder. Light green; hairs characteristic, and calcium oxalate 

 in rosette aggregates. 



GOSSYPIUM PURIPICATUM. Purified Cotton. The hairs of the 

 seeds of Gossypium hirsutum, G. barbadense, and other species of 

 Gossypium (Fam. Malvaceae), biennial or triennial shrubs indige- 

 nous to sub-tropical Asia and Africa, and cultivated in all tropical 

 and sub-tropical countries. The seeds are hand-picked, freed from 

 dust by screens or drums, and the cotton removed in the cotton- 

 gin. It is then freed from mechanical impurities, deprived of fatty 

 and other substances and finally bleached. It is estimated that 

 1,000 million K. of cotton are produced annually. Long staple or 

 sea-island cotton is obtained from G. hirsutum, while short staple 

 or upland cotton is derived from G. barbadense. 



Description. A white, soft tufted mass, consisting of some- 

 what flattened, twisted and spirally striate, 1-celled, non-glandular 

 hairs, from 2.5 to 4.5 cm. in length; inodorous and tasteless. 



Absorbent cotton is soluble in ammoniacal solution of cupric 

 oxide, yields less than 1 per cent of ash, and on treating it with 

 water, the solution should have a neutral reaction and not give any 

 reaction with ammonium carbonate, barium chloride, mercuric 

 chloride or silver nitrate. 



Adulterants. Various substances may be added to absorbent 

 cotton to increase the rate of absorption of water, as chlorides of 

 calcium, magnesium and zinc, glycerin and glucose; loading mate- 

 rials, as barium and calcium salts, and clay are added to inferior 

 grades of the article. 



