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SUMMARY OF CURRENT RESEARCHES RELATING TO 
BOTANY. 
A. GENERAL, including the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-structure and Protoplasm. 
Elementary Structure and Growth of Living 1 Substance.* — In this 
very important work, Prof. J. Wiesner further explains his views on the 
structure and growth of the living cell and of the substances of which 
it is composed. 
All the properties of living structures can only be derived from 
similar properties in previously existing living structures, and must 
have been propagated by division ; and on this process of division 
depends also ultimately even sexual reproduction. That vegetative 
reproduction depends entirely on the specialized capacity of certain cells 
for division is shown by the propagation of Begonia from fragments of 
leaves. Any meristem-coll which gives birth to a new individual may 
be compared to an impregnated ovum-cell, and is termed by Wiesner a 
“secondary embryonic cell.” The difference between projiagative cells 
which can originate new individuals in a non-sexual way and ordinary 
vegetative cells, is that the former contain far more germ-plasm. The 
transformation of resting-cells into meristem-cells, i. e. into propagative 
cells, is effected by the passage into them of plastic substances out of 
neighbouring cells. In both animals and plants the formation of organs 
depends entirely on cell-division ; all visible new-formations of the 
living organism are produced by division. But this capacity for division 
of the living substance is not unlimited ; it does not go so far as the 
breaking up into molecules. 
The composition of living substance out of minute plasomes bolds 
good not only for such bodies as pyrenoids and starch-grains, but also 
for protoplasm and the cell-wall ; and these plasomes the author states 
to be directly visible. The cell-wall of living cells consists by no means 
exclusively of cellulose, though cellulose is one of its most important 
ingredients; it very often contains protoplasm. That the cell-wall is 
not entirely passive in the vital phenomena of the plant is shown by a 
great variety of circumstances. Dr. Wiesner does not, however, agree 
with previous writers as to the physical structure of the cell-wall. He 
states that it is composed of fine fibrillm, and these again of very delicate 
roundish particles, the dermatosomes ; the best mode of demostrating 
these is by subjecting the cell-wall to the influence of chlorine water 
for weeks. 
The structure of the protoplasm is not the same in all cells. In 
many cases it forms a network ; in others it is composed of interwoven 
threads ; while in others again it has a honeycomb-like structure ; and 
the structure may vary in one and the same cell. In hyaline and 
homogeneous protoplasm the plasomes are probably not closely crowded, 
as they are in the cells of a meristematic tissue. The nucleus is, like 
* ‘ Die Elementarstruktur u. d. Wachstum d. leb. Substanz,’ Wien, 1892, 283 pp. 
See Biol. Centralbl., xi. (1891) p. 705. Cf. this Journal, 1891, p. 207. 
