STRUCTURE OF SEED. 195 



its entire absence is frequent in Dicotyledons ; of the 

 families of this class, about a third are constantly devoid 

 of it. 



The nature of the albumen presents great variety in 

 the different families, and a remarkable constancy in 

 each of them. 



1st. One of its most ordinary states is that of being 

 fleshy, as is seen in the Cinchonaceae. This fleshy state 

 degenerates into a firm and almost woody texture in 

 some families, as in the Umbelliferae. 



2d. It is often oily, as is seen in several Palms, and 

 especially in the Euphorbiaceae, in which we remark 

 that their embryo is also impregnated with oil, but that 

 the nature of these two fixed oils is different; that of the 

 embryo is acrid, as is the entire plant, of which the em- 

 bryo is a miniature representation ; that of the albumen, 

 which is a particular secretion of an organ, is in general 

 bland and wholesome, although more or less laxative. 



3d. It is frequently feculent or farinaceous, as is 

 observed in the Caryophylleae, Nyctagineae, and espe- 

 cially in the Gramineae ; for it is the albumen of the 

 Cereal Gramineae which serves for the principal nourish- 

 ment of the human species. 



4th. We find horny albumens, such as that of the 

 Asparageae, the Coffeaceao, &c. 



All known albumens are of a wholesome nature, to 

 whatever family they belong ; those of the Euphorbiaceae 

 are laxative ; their properties are also similar in all those 

 which have an analogous consistence. Thus, all farina- 

 ceous albumens are sensibly of the same nature ; the 

 farinaceous albumen of the Polygoneae, for example, 

 may be substituted for that of the Gramineae : all horny 

 ones present some analogy with that of the Coffee ; thus 

 those of Galium and Ruscus, when roasted, have the 

 odour of Coffee. 



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