COEK. 



[ 210 ] CORPORA AMYLACEA. 



C. elegans. Shores of Denmark. 



BiBL. Heiberg, Consi). Died. 1863, 53, 

 pi. 3. tig. 8. 



CORK. — Ordinarily the outer layer of 

 bark of the Cork Oak ( Quercus Suber), for 

 the deTelopmeut of which, see Bark. Ver- 

 tical and trausverse sections of the large 

 liirht-coloured cells of cork are shown in 

 PI. 47. figs. 16 and 17. The term cork is 

 applied generally to excessive developments 

 of the suheroiis layer of barks. 



CORN. — The general name applied to 

 the seeds, or rather the fruits of the various 

 plants furnishing the ordinary materials for 

 bread. These all belong to the Mouocoty- 

 ledonous family, Graminacese (Grasses) ; for 

 Buck-wheats cannot be considered as true 

 corn, The grains of the Grasses are enve- 

 loped in the adherent pericarp, which is dry 

 and smooth ; the seed which this encloses is 

 characterized by the presence of a compara- 

 tively larger mealy albumen, composed of 

 thin-walled parenchyma, more or less densely 

 filled with starch, which makes up the great 

 body of the grain ; a few layers of cells sub- 

 jacent to the surface, however, contain little 

 starch, but abundance of nitrogenous proto- 

 plasmic matter, or yliden. These layers 

 containing the greater proportion of the 

 gluten, together with epidermis, are removed 

 from fine flour in grinding, as the bran and 

 pollard — the fine white flour consisting 

 chiefly of the starch. The forms of the 

 starch-grains difter considerably, as also 

 their condition in the cell (PI. 46). In 

 Wheat {Tritiaim), the starch-grains are 

 lenticular (fig. 8), and lie loose in the cells ; 

 in Barley (Jfordewn) , they are very similar, 

 but the larger grains are squarish and 

 thinner (fig. 9) ; in Oats (Aveiia), polygonal, 

 but compacted together into roundish 

 masses (fig. 10) ; in Rice (Oryza) , the starch- 

 grains are veiy small, and packed so 

 closely together that they press upon one 

 another, thus acquiring a parenchymatous 

 form (figs. 12 & 13) ; and then, as they ad- 

 here firmly together, the contents of the cells 

 appear like one solid mass; hence the horny 

 character of the grains of rice, and the grit- 

 tiness of rice-flour. In Maize (Zca), the 

 outer part of the grain is horny from the 

 same cause as rice, and presents a similar 

 appearance (fig. 3), but in the centre the 

 cells are often less densely filled, and the 

 grains lie more or less loose (fig. S). For 

 further particulars of the characters of 

 the starch-grains, see Starch. 



CORNEA. See Eye. 



CORNICULA'RIA, Ach.— A genus of 

 Lichens = ^/ec;'o;-/« pt. 



CORNS consist of thickened epidermis, 

 the scales being increased in number, much 

 flattened, and closely aggregated from pres- 

 sure. This is the structure in their simplest 

 form. When larger they represent an ordi- 

 nary bhster, conjoined with the thickening 

 of the epidermis ; hence the origin of the 

 cavity in the centre of many of them. The 

 papillfe of the cutis are generally hypertro- 

 phied. The epidermic scales may be ren- 

 dered distinct by digestion with acetic acid 

 or solution of potash. 



CORNUSPI'RA, Schultze.— This genus, 

 restricted, comprises the planorbiform 3Iili- 

 olida, which, commencing with a somewhat 

 agathistegian growth, soon become discoi- 

 dal and non-segmented. 



C.fol/acea (Pi. 23. fig. 13) is a common 

 Foraminifer, white and opaque, with the 

 whorls rapidly increasing in width in the 

 adult state. It has abounded from the 

 older Tertiary times to the present, chiefly 

 in shallow water, but found at 530 fathoms, 

 North Atlantic, by Carpenter. 



BiBL. Carpenter, Foram. 68 ; Pr. Roy. 

 Soc. 1869; Schultze, Ann. N. H. 1861, 

 306. 



COR'PORA AMYLA'CEA.— These are 

 microscopic rounded bodies, exhibiting a 

 number of concentric rings, and somewhat 

 resembling starch-grains in appearance. 



They are found in 

 the/orau', 'Cn^septuin 

 lucidum, the walls of 

 the ventricles, and the /( 

 cortical substance of ' 

 the brain, the me- 

 dullary substance of ^ 



the spinal cord, the Magnified 350 diameters- 

 waxy spleen, &c. 

 They are but little 

 acted upon by dilute 

 acids; caustic alkalies render them more 

 transparent, and gradually dissolve them. 

 Solution of iodine gives them a bluish tinge ; 

 and the subsequent addition of sulphuric 

 acid produces the bluish-violet colour seen 

 when cellulose is treated with these reagents. 

 The reaction is best seen when the action of 

 the acid takes place slowly. Hence these 

 bodies have been regarded as consisting of 

 amyloid or cellulose. 



The corpora amylacea must be distin- 

 guished from the concretions forming ' brain- 

 sand,' or the acervulus cerebri. These are 

 also rounded, single, or aggregated, usually 



Fig. 



143. 



Corjiora amylacea, from 

 the hiuuan ependyma. 



