. A compendium of general botany. Plants. THE CELL. first claim our attention. The water-bearing cavities (vacuoles) in- crease more and more in size and subsequently come in contact and become flattened by mutual pressure. Finally they are separated only by thin plasmic membranes and threads; when these break the vacuoles flow together to form one. The plasm then lines the inner surface of the cell-wall as a membrane which is usually very thin, but which is never absent from the liv- ing cell. This membrane is called the jprimordial xdricle or plasmic utricle. On account of its frequently imm
. A compendium of general botany. Plants. THE CELL. first claim our attention. The water-bearing cavities (vacuoles) in- crease more and more in size and subsequently come in contact and become flattened by mutual pressure. Finally they are separated only by thin plasmic membranes and threads; when these break the vacuoles flow together to form one. The plasm then lines the inner surface of the cell-wall as a membrane which is usually very thin, but which is never absent from the liv- ing cell. This membrane is called the jprimordial xdricle or plasmic utricle. On account of its frequently immeasurable thinness it is invisil)le as long as it is in contact with the cell- wall. If by artificial means the plasmic utricle can be caused to separate from the wall by contraction, then this is looked upon as giv- ing evidence that it was a living cell. (Compare Fig. The cell-wall and the plasmic utricle, the two coverings of the cell con- tents, differ (1) chemically, in that the primordial utri- cle being a part of the plasm is an albuminoid substance, while the cell-wall belongs to the group of carbohy- drates and contains there- f ri TT /I rk +T 1 +f ^^^- 1-—Young parenchyma-cell of Zea Mays. tore U, ri, and U, the latter ^, nomml; S, plasmolyced. w, membrane; p and in +liP nrnrinrtinn fn iriv^y, ''• protoplasmic utricle; n, nucleus; s, cell-lumen in tne proporuon to lorm ^jtb gap. (After Frank.) water (H.^0); (2) physically, in that the cell-wall is highly elastic with but little extensibility, while the plasmic utricle is very ex- tensible and only slightly elastic. To this must be added a second physical difference, that of diosmosis. The physical differences are. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Westermaier, Max; Schneider, Albert, 1863-1928. New York : Wiley
Size: 1084px × 2306px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectplants, bookyear1896
