ALBERTIA. 



C 26 ] 



ALBUMEN. 



ALBER'TIA. A genus of Rotatoria. 

 See ALBERTINA. 



ALBERTI'NA. A family of Rotatoria 

 (Dm.). 



Char. Body, cylindrical, vermiform, 

 rounded in front, with an oblique orifice, 

 from which the ciliated organ, scarcely 

 broader than the body, projects, terminated 

 behind by a short conical tail. Jaws for- 

 ceps-like, simple or unidentate. 



This family contains only a single genus, 

 and this a single species, A. vermiculus 

 (PI. 43. tig. 4), which lives parasitically in 

 the intestines of worms (JLumbrici) and 

 slugs (Limaces). Length 1-47 to 1-79". 



Within the body are seen- ova and young 

 in various stages of development. The 

 ciliated apparatus in front of the mouth is 

 surmounted by a hood-like appendage. 



ALBU'MEN (Chemical). A proximate 

 principle of animal and vegetable bodies, 

 with which we are familiar as occurring in 

 the white of egg. It exists in two states, 

 uncoagulated and coagulated. At a tempe- 

 rature of 160 F. it is reduced from the 

 former into the latter condition. It is 

 reddened by Millon's test ; is insoluble in 

 acetic acid ; is rendered purple by Petten- 

 kofer's test, but the reaction requires some 

 time for its production. In the coagulated 

 state it is distinguished from fibrine by the 

 action of acetic acid, and by its insolubility 

 under prolonged digestion at a heat of 

 110 F, with solution of nitrate of potash. 

 When heated with strong muriatic acid, it 

 is coloured purple. 



It possesses no microscopic characters; 

 when coagulated, it appears to consist of 

 extremelv tine amorphous granules. 



ALBUMEN, or PERISPERM (of seeds). 

 This is a technical term used in Botany to 

 denote the cellular structure which exists in 

 greater or less quantity in all seeds where 

 the development of the embryo is not accom- 

 panied by the entire absorption of the 

 nucleus of the ovule. When the embryo 

 does so displace the nucleus, it becomes 

 immediately invested by the seed-coats ; in 

 other cases it is found imbedded in a mass 

 of cellular tissue of varying structure, which 

 is the t albumen.' The structure of albumen 

 corresponds to that of the cotyledons of seeds 

 devoid of albumen, both serving the same 

 office, namely that of reservoir of nutriment 

 for the germinating seed. This nutriment 

 may be laid up in different conditions 

 namely, in the state of starch, oil, aleurone, 

 or of cellulose, and in the last case in a soft 



and fleshy, or a hard and horny condition. 

 Combined conditions are often met with in 

 the same structure, as when a fleshy tissue 

 contains starch or oil in the cavities of its 

 cells, &c. 



Starchy, mealy, or farinaceous albumen 

 constitutes the chief part of the seeds of 

 many plants, especially of those of the Grass- 

 tribe, and is that portion of the corn-grains 

 whence white flour is obtained. Here the 

 cellular tissue is composed of membranous 

 cells densely filled with starch-grains (P1.46. 

 fig. 3). The edible portion of the cocoa-nut 

 is the corresponding region of that seed, and 

 affords us a good example of an oily albu- 

 men, composed of tolerably thick-walled 

 cells filled with a viscid mucilage, in which 

 numerous oil-globules are suspended. The 

 stone of the Date, the nut of the Areca 

 Palm (PI. 47. fig. 21), are good examples of 

 a horny albumen, the cells possessing walls 

 of extreme thickness, traversed by pores and 

 formed, like wood-cells, by the deposition of 

 successive layers. In the ripe seed the 

 structure of this horny albumen is generally 

 much disguised, and a section exhibits the 

 appearance of a homogeneous horny sub- 

 stance excavated into irregular cavities. By 

 applying dilute sulphuric or sulpho-chromic 

 acid, the true boundaries of the cells may 

 generally be distinguished, and often even 

 the lamination of the walls (PI. 47. fig. 22). 

 The substance called Vegetable Ivory is the 

 albumen of the seed of the Phytelephas 

 Palm, and is an instance of an extreme de- 

 gree of development of the cellulose albumen, 

 vying with the hardest woods in the solidity 

 of its cell-walls, A thin section of this albu- 

 men, especially if treated with acid, at once 

 reveals the cellular structure of this dense 

 substance (PI. 47. fig. 23). The true struc- 

 ture may also be detected by the help of 

 polarized light (see POLARIZATION). The 

 cotyledons of many seeds are, as above 

 stated, formed of elementary structures 

 resembling those of albumen. We find 

 them farinaceous, fleshy, or oily, but rarely 

 attaining to a very great degree of solidity 

 in the horny forms. The cotyledons of beans 

 are composed of a fleshy cellular tissue 

 with thick, porous walls, coloured blue by 

 iodine alone (amyloid), while the cavitie's 

 of the cells are tilled with starch-grains. 

 The cotyledons of the almond, nut, &c. 

 are examples of fleshy cells containing 

 abundance of oil-globles. 



The albumen of seeds may be formed by 

 the development of the tissue of the nucleus 



