THE ENERGY OF THE LIVING PROTOPLASM. l6l 
Plant-cells deprived of their nucleus are incapable of trans¬ 
forming starch into cellulose ( Klebs ). They evidently cannot bring 
on a sufficient saccharification of the starch granules, to provide 
the cytoplasm with the necessary amount of sugar. For the 
lowest animal forms, an analogous case was proved by B. Hofer ; 
amœbæ can no longer digest albuminous particles when deprived 
of their nucleus. The importance of the nucleus for the secretion 
processes of animal organisms was also observed by Verworn, 
Balbiani, and Korschelt . The latter found, for example, consi¬ 
derable changes of form of the nuclei in insects during the 
secretion of chitin. 
The vegetal nucleus seems to be also the manufacturer of 
the proteids, as first suggested by Strassburger and Schmitz ; 
at least protein-crystalloids are frequently found in the nuclei 
of plant-cells, especially in the orders, Oleaceœ, Scrophularineœ , 
Bignoniaceœ, and in the Pteridophytes (Zimmermann). For, 
it does not seem probable that this protein has its source in 
the cytoplasm and is then transported into the nucleus for 
crystallisation. Again, in germinating seeds, where protein 
formation from fragments of decomposed reserve-proteids proceeds 
with considerable readiness, the nuclei (and also the nuc¬ 
leoli) increase in size. (I) The most important function of the 
nucleus, however, is connected with the division and multiplica¬ 
tion of cells and with sexual propagation in plants and animals. 
(i) Peters, Botan. Centralbl. 48 ,181. The nuclei are also often relatively large 
in the epidermis-cells of leaves, which are especially adapted to store up larger 
quantities of active albumen ( Bokorny , Pflüg. Arch 55, 142). Also in the cells of 
glands relatively large nuclei are often present. 
It is also a remarkable observation that plant-cells deprived of their nucleus do 
not produce any more starch by assimilation. Only certain algæ, containing 
pyrenoids (Zygnemaceæ) have thus far been observed to be exceptions in regard 
to starch-production under this condition (Klebs). Simpler organisms, like amœbæ 
and algæ, are especially well suited for experiments with isolated cytoplasm. Klebs 
has, by plasmolysis, Gcrashnoff by low temperature during the process of karyokinesis, 
obtained living parts of algæ-cells, or living cells without a nucleus. The life of such 
cytoplasm, however, did not last longer than about six weeks. On the other hand the 
nuclei of radiolaria can remain alive, if deprived of the cytoplasm, only 10-15 hours. 
Nucleus and cytoplasm influence each other by certain of their products (Verworn 
Pflüg , Arch. 51 , 1 13). 
