. The microscope and its revelations. s into two halves, a and a; C, cell insame stage, showing contraction of endoplasni(produced by addition of wateri into two sepa-rate masses round the two segments of originalnucleus; D, two complete cells within mother-cell, divided by a partition. imbedded in its residual endoplasm, cadi proceeding to complete itself as a cell by theformation of a limiting wall of eellullose (fig 414). As a newgeneration in any phanerogamic plant has its origin in thefertilisation of a highly specialised germ-cell (contained AVI thintin- ovule) by the contents of a sperm
. The microscope and its revelations. s into two halves, a and a; C, cell insame stage, showing contraction of endoplasni(produced by addition of wateri into two sepa-rate masses round the two segments of originalnucleus; D, two complete cells within mother-cell, divided by a partition. imbedded in its residual endoplasm, cadi proceeding to complete itself as a cell by theformation of a limiting wall of eellullose (fig 414). As a newgeneration in any phanerogamic plant has its origin in thefertilisation of a highly specialised germ-cell (contained AVI thintin- ovule) by the contents of a sperm-cell (the pollen-grain).so do we find, among all save the lowest cryptoyains, a provisionfor the union of the contents of two highly specialised germ-cells being fertilised by the access of motile protoIlasmie 1 todies (anthero/.oids), set free from the cavities of the-pii-m-cells within which they were developed. Hut althoughthe sexual process can lie traced downwards under this form into PROTOPLASM OF THE LIVING CELL 537. FIG. 414.—Successive stages of frei-cfU /u in embryo-sac of seed of scarlet-runner; a, a, a,completed cells, each having its proper cell-wall,nucleus, and endoplasm, lying in a protoplasmicmass, through which are dispersed nuclei and cellsin various stages of development. the group of thallophytes, we find among the lower types of thatgroup a yet simpler mode of bringing it about; for there is strongreason to regard the act of conjugation which takes place inthe Conjugate and in some fungi in the same light, and to lookupon the zygospore,1 which is its immediate product, as theoriginator (like the fertilised embryo-cell of the phanerogamic seed)of a new attentionhas recently beenpaid by Strasburgerand others to the con-stitution of the endo-plasm and to theprocesses connectedwith cell-division. Onboth these subjects itis impossible here togive more than thebarest outlines. Stras-burger distinguishesbetween the followingdifferen
Size: 1855px × 1347px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
