56 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Unity of Protoplasm.* — Herr J. G. Vogt asserts that the theory of 
a uniform protoplasm which contains all the future germs of life cannot 
be maintained in the face of our present knowledge with regard to its 
properties. The organic elements are the monoplasts ; they are the 
products of chemical processes, and vary in accordance with the condi- 
tions under which they are formed. These specifically distinct mono- 
plasts are grouped into polyplasts, of which there are two chief kinds, 
those which are composed of similar, and those which are composed of 
dissimilar monoplasts. All micro-organisms, and all cells of more 
complicated organisms, are structures of a fourth or higher order, 
colonies of polyplasts. The production of species, and every kind of 
development, is dependent on the power of the monoplasts to adapt 
themselves to chemical changes. 
Minute Structure of the Cell-wall, f — Herr C. Correns has made a 
series of observations, for the purpose of determining the nature of 
the striation of the cell-wall, chiefly on epidermal cells of Hyacinthus 
orientals, and on bast-cells of Neriurn Oleander, Vinca minor, major, and 
herbacea, and Apocynum androssemi folium. The striation arises either 
from unequal thickening or from differentiation. It is usually spiral, 
the space between the coils varying greatly. The author is unable to 
determine the cause of the differentiation. The striation of bast-cells is 
also often due to differences in the amount of water contained, though 
this is not always the case. In the growth of starch-grains, the question 
is left undecided whether it is due to splitting, as Niigeli thought, or to 
the apposition of lamella) and subsequent differentiation. 
Cell-nucleus in Seeds.J — Herr T. Peters has investigated the condi- 
tion of the cell-nucleus in the seeds of a large number of plants during 
their development, rest, and germination. The general results obtained 
were as follows. 
The presence of nucleoles was determined in a large number of cases 
where they had not previously been detected ; as in the cells of the 
endosperm and embryo of dormant seeds of Conifers (Picea vulgaris, 
Larix europsea, Biota orientalis ) ; in the reserve-material cells of starchy 
seeds ( Pisum , Vicia Faba, Leucojum a sstivumj ; in those of some seeds 
destitute of starch ( Pseonia , Asphodelus albus, Corylus Avellana'). In 
Carex and Sparganium there is a considerable increase in the number of 
nuclei and nucleoles before the formation of the albuminoid-crystalloids 
and starch. The formation of these crystalloids takes place, in these plants, 
in the interior of a drop-like collection of proteid substances, by a process 
of crystallization. In Bicinus and Cucurbita the crystalloids break up 
during germination into fragments which are gradually absorbed. In 
Carex the formation of starch commences in the immediate neighbour- 
hood of the nucleus, and it finally completely incloses it. In all ger- 
minating seeds a considerable increase takes place in the size of the 
nucleus, and especially in that of the nucleoles. In the nuclei of 
* ‘ Das Empfindungsprincip u. d. Protoplasma, auf Grund eines einheitlichen 
Substanzbegriffes,’ 8vo, 208 pp., Leipzig, 1891. See Bot. Centralbl., xlvii. (1891) 
p. 336. 
f Jahrb. f. Wiss. Bot. (Pringsheim) xxiii. (1891) pp. 254-338 (2 pis. and 2 figs.). 
X ‘ Unters. iib. d. Zellkern in d. Samen wahrend ihrer Entwick., Buhe, u. 
Keimung,’ 31 pp., Braunschweig, 1891. See Bot. Cenlralbl., xlviii. (1891) p. 180. 
