ALBERTIA. 



[ 22 ] 



ALBUMEN 



tion of the stalk by which it is attached to 

 the rocks. It grows from 4 to 12 feet long. 



Alaria esculenta, Grev. 



ALBERTIA.— A genus of Rotatoria. See 

 Alberttna. 



ALBERTINA.— A family of Rotatoria 

 (Duj.). 



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 forceps- 

 like, simple or unidentate. 



This family contains only a single genus, 

 and this a single species, A. vermiculus 

 (PL 34. fig. 4), which lives parasitically in the 

 intestines of worms {Lumhrici) and slugs 

 {Limaces). Length 1-47 to 1-79". 



Within the body are seen ova and foetus 

 in various stages of development. The cili- 

 ated apparatus in front of the mouth is sm*- 

 mounted by a hood-like appendage. 



ALBUMEN (Chemical). — A proximate 

 principle of animal and vegetable bodies, 

 with which w^e are familiar as occurring in 

 the white of egg. It exists in two states, 

 uncoagulated and coagulated. At a tempe- 

 rature of 160° F., provided no free alkali is 

 present, it is reduced from the former into 

 the latter conchtion. Its chemical relations 

 to other proteine compounds are not very 

 firmly established. It is reddened by Millon's 

 test ; is insoluble in acetic acid ; is rendered 

 purple by Pettenkofer'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 colom*ed purple. 



Albumen possesses no microscopic charac- 

 ters ; when coagulated, it appears to consist 

 of extremely fine amorphous granules. See 

 Proteine. 



BiBL. See works on Chemistiy; Brande's 

 Chemistry ; Lehmann's Physiol. Chemie. 



ALBUMEN (of seeds).—Thisis 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 accompanied 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 ' 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 

 diff^erent conditions, namely, in the state of 

 starch, of oil, 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 structvu-e, 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 (PI. 36. 

 fig. 1 c). The edible portion of the cocoa-nut 

 is the corresponding region of that seed, and 

 affbrds us a good example of an oily albu- 

 men, composed of tolerably thick-walled 

 cells filled with a viscid mucilage, in which 

 abundance of oil-globules are suspended. 

 The stone of the Date, the nut of the Ai'eca 

 Palm (PI. 38. fig. 21), are good exam^Dles 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 in irregular cavities. By 

 applying dilute sulphuric acid, the true 

 boundaries of the cells may generally be di- 

 stinguished, and often even the lamination of 

 the walls (PI. 38. fig. 22). The substance 

 called Vegetable Ivory is the albumen of the 

 seed of the Pliytelephas Palm, and is an 

 instance of an extreme degree of develop- 

 ment of the cellulose albumen, vicing with 

 the hardest woods in the solidity of its cell- 

 walls. A fine section of this albumen, espe- 

 cially if treated with acid, at once reveals the 

 cellular structme of this dense substance 

 (PL 38. fig. 23). The cotyledons of many 

 seeds are, as above stated, formed of element- 

 ary 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 form. The cotyledons 

 of beans are composed of a fleshy cellular 

 tissue with thick, porous walls, coloured 

 blue by iodine alone (amyloid), while the 

 cavities of the cells are filled with starch- 

 grains (PL 36. fig. 20). The cotyledons of 



