1887] The Significance of Sex. - 161 
olus, and in that case this body is a paranucleolus over against 
the mitom. But these bodies may have come from the plasmatic 
nucleolus of Carnoy, and so we are still in doubt. 
nother unsolved problem is concerning the connecting fibres 
that remain between the retreating karyosomata. In plants they 
help to build the cell-plate, and the nucleus gets reconstructed 
without their being absorbed. In animals they seem to be ab- 
sorbed, for, if left outside, they form the paranucleus of Platner 
(see Fig. 123), which is later absorbed by the nucleus to form 
the spindle. They are thus made of substances similar to those 
which enter into the parachromatic reticulum, and, when not 
absorbed by the nucleus, they join the other fibres of the cyto- 
-plasmic reticulum, from which they can no longer be distin- 
guished. Thus the chromatin of the nucleus must make more 
hyaloplasm, from which a new parachromatic reticulum can 
arise. 
There is some evidence of the existence of microsomata that 
are not chromatin; in the cytoplasmic reticulum these are not so 
active in their fusions and segmentations as the nuclear microso- 
mata, but still they do this, for the spindle-fibres and rays, when 
extra-nuclear, have been observed to segment and fuse. This 
can easily be understood by combining with Heitzmann’s schema 
the idea of units in the cell. Strasburger and Pfitzner recognize 
the microsoma as such a unit, and we have shown that there are 
numerous units of differing complexity and degrees. When 
two organisms differ in the number of units that enter into their 
structure, such difference is one of degree in the ordinary sense, 
but when two organisms differ by belonging to higher or lower 
stadia of organization, such difference constitutes a discrete degree. 
Such degrees separate the Protozoa from Metozoa, a man from 
the social organism, a cell from the microsoma, a microsoma from 
a gemmule. Though here further study is needed to discover 
the number of stadia visible to the microscope, Nageli has ad- 
meaty discussed the stadia that lie between the chemical mole- 
a NS, a 
icell „and Altmann | 
Ppa aes, HL 
that the bacterial 
organisms are of the same grade of organization as the microsoma. 
Each node in a reticulum may be conceived as a unit. We have 
already seen how, when chromatin segments, it may leave a funic- 
ulus of hyaloplasm (with or without a wall). This connecting 
piece of hyaloplasm may break by beiig drawn towards the 
