album Græcum

[Lat. ( lit. ) = Greek white.] A name given to the excrement of dogs, which becomes white as chalk by exposure to the air. It is used also of the dung of hyenas, which is almost of the same composition as bone, and nearly as durable; among other places it has been found abundantly in a fo il state in the celebrated Kirkdale Cavern, twenty-five miles N.N.E. of York, described by Dr. Buck land in his Reliquiæ Diluvian a. ǎl-bū-měn, ăl-bū-min, s. [Lat., whence Fr. albumine, Port. album in a, Ital. albume.] 1. Chem . The name of a cla of Albuminoids (q.v.) that are soluble in water, as serum (q.v.) and egg albumen. Egg albumen differs from serum by giving a precipitate when agitated with ether; it is scarcely soluble in strong nitric acid; its specific rotation is 35 50 for yellow light. The white of eggs is composed of this substance; it dries up into a light yellow gum-like substance, which will not putrefy. It is converted into coagulated albumen by heating the fluid albumen to 72° C. It contains sulphur, and blackens a silver spoon. It is precipitated by strong acids. It is an antidote in cases of poisoning by corrosive sublimate or copper salts. Coagulated albumen is obtained by heating neutral solutions of albumen, fibrin, ., to boiling, or by the action of alcohol, also by heating precipitated albuminates or casein. It is insoluble in water, alcohol, and scarcely in dilute potash, but di olves in acetic acid; by the action of caustic potash it is converted into albuminate. Pepsin and HCl (hydrochloric acid), at blood-heat, converts it into syntonin, and then into peptone. Derived albumins are insoluble in water, and in solutions of NaCl (sodium chloride), but soluble in dilute acids and alkalies. There are acid albumins and alkali albumins. Acid albumin is formed by adding a small quantity of dilute HCl (hydrochloric acid) to serum or egg albumen, and gradually raising the temperature to 70°; it does not coagulate, and the rotation to the left is increased to 72°. By neutralizing the liquid, a white flocculent precipitate is obtained insoluble in water, but solubie in alkali and in dilute solutions of alkaline carbonates. Alkali albumin , or albuminate , is obtained by adding very dilute caustic alkali, heating the liquid, and precipitating with acids. It closely resembles the casein of milk. Pota ium albuminate is also called protein . 2. Bot. A substance interposed between the embryo and the testa of many plants. It is sometimes soft and fleshy, and at other times hard. It varies greatly in amount in those plants in which it is present, being particularly large in some endogens, such as the cocoa-nut, in which it constitutes the eatable part of the fruit. It is the perispermium of Ju ieu, and the endospermium of Richard. (Lindley: Int . to Bot . , 3rd ed., 1839, pp. 24, 249.) 3. Phot. Albumen Proce : A proce by which albumen is used instead of collodion to coat gla or paper. A method of doing this in the case of gla was published by M. Niépce de Saint Victor in the Technologist for 1848. It was subsequently improved by M. le Gray. The foreign transparent stereoscopic views were at one time obtained by the use of albumen in the way now described.