THE ENERGY OF THE LIVING PROTOPLASM. 
163 
nucleus was observed by Klebs and Haberlandt, (J) so that 
it is probable that the nucleus prepares the proteids suitable 
for the purpose of organisation. The vegetal nucleus performs 
this by far-reaching synthesis', the animal nucleus by transform¬ 
ing the resorbed peptone. 1 (2) 3 
Clearly, the nucleus of the living cell cannot be identical 
with that of the dead, and the nuclein known to chemists, ex¬ 
tracted with alkalies and precipitated with acids, is a relatively 
stable compound, which would be entirely incapable of serving 
the physiological phenomena of karyokinesis, which are made 
possible only by a highly labile state of the proteid composing 
the nucleus. 1(3) 
Division of labour, still of restricted compass in a single 
plant-cell, keeps growing in importance and extent with the 
development of multicellular organisms, plants as well as 
animals. Some cells serve mechanical devices, others do 
(1) Biol. Centralbl. s, 133. 
(2) I consider the process of organisation as a sort of polymerisation, in which 
only molecules of equal configuration can participate, and in which isomeric and stereo- 
isomeric molecules would be hurtful, the mutual reaction of their labile groups being 
facilitated (Cf. O. Loew, Natural System of Poisonous Actions, Ch. V. On the 
poisonous proteids , 82). This, again, would imply a specific tectonic for the nuclei 
of different species as the necessary condition for yielding one and the same active 
albumen for the organisation of each cytoplasm. This view could also furnish a 
plausible explanation of certain observations in regard to the propagation of the 
species. A specific configuration of the nuclein will naturally lead to a specific 
tectonic of the nucleus, i.e., the invisible anatomical structure will be in close connec¬ 
tion with the configuration of the proteid. Such considerations may finally also 
throw some light upon the fact, that the fibrins, the oxyhæmoglobins, the alexines of 
different species are by no means identical. The possible stereo-isomers of a proteid 
reach evidently to an immense number, even if we start from one and the same 
active peptone. [Stereo-isomerism conceives of compounds as containing the same 
elements in the same proportion and arranged in the same groups, and yet differing 
in properties, because of a different arrangement in space of the constituent groups]. 
(3) Various observations prove that the nucleus is even of much greater lability 
than the cytoplasm. The problem of karyokinesis appears still more complicated now 
that the centrosomes have been observed, initiating the division. 
Differences have been observed between the nuclei of nerves, glands, and 
muscles ; further, between those of the male and female sexual cells, the former being 
richer in nuclein ( E. Zaccharias). Still greater must be the differences between the 
nuclei of the germ-cells and those of the somatic cells, especially in animals. 
