Cotton is used extensively in bacteriological laboratories as a filter of liquids and gases. This property possessed by cotton, of retaining in its fibers the germs of the air was utilized by the famous French surgeon Guérin in the treatment that bears his name. The denuded surfaces exposed to infection by airborne bacteria are completely protected against them when, according to the Guérin treatment, they are enveloped in large masses of fresh, raw cotton, presumably free from microörganisms. To avoid the possibility of infection by the cotton itself, it is now the practice to sterilize it either by means of chemicals such as carbolic acid, iodoform, etc., or by physical means such as high temperatures. Raw cotton is used in compounding gun cotton or explosive cotton, also named _pyroxylin_, and this is used to make collodion, so extensively employed in medicine. Pyroxylin is made by treating cotton with equal parts of nitric and sulphuric acids, then washing with water till the latter ceases to give a precipitate with chloride of baryta; then dry in the air. Collodion is made by dissolving 5 grams of pyroxylin in the following mixture: Sulphuric ether, rectified 75 grams. Alcohol at 95° 20 grams. Filter. Elastic collodion: Canada Balsam 1.50 grams. Castor oil .50 grams. Collodion 30.00 grams. Mix. Botanical Description.--A plant 2-3° high, of herbaceous stem, branches sparsely covered with small, black points; leaves cleft at their base, with 5 lobules and a small gland on the midrib. Petiole long with 2 stipules at the base. Flowers axillary, solitary. Calyx double; the outer portion divided in 3 parts, heart-shaped, and each with 5-9 long, acute teeth. Corolla bell-shaped, of 5 petals, pale yellow or turning rose color, purple at the base. Stamens many, inserted on a column. Stigma in 4-5 parts. Ovary of 3-5 compartments. Seeds enveloped in the fiber. Habitat.--Batangas, Ilocos. _Bombax malabaricum_, DC. (_B. Ceiba_, Blanco.) Nom. Vulg.--_Taglinaw_, _Bobuy gubat_, Tag.; _Talutu_, Vis. Uses.--In India the roots are used to obtain an astringent and alterative effect and form part of a well-known aphrodisiac mixture called _Musla-Samul_. If the trunk is incised, an astringent gum exudes and this they use in diarrhoea, dysentery and menorrhagia. Dose of the gum 2 1/2-3 grams.