172 W. WALDEYER. 
mencement of the “skein” only a single thread is present, 
which is greatly coiled and so has the appearance of a large 
number of separate loops. So difficult is it, as I know from 
experience, to be positive on this point, that I might agree 
with Rabl when he says that from the commencement nume- 
rous separate loops—as many as twenty in animal cells— 
are present. 
Strasburger, too, in his later contribution (191) has given 
up his earlier views as to the presence of only a single thread. 
In the cells of Chironomus-larva, where Balbiani first recog- 
nised it, Strasburger has also admitted a single thread. Rabl, 
differing from his predecessors, describes the already men- 
tioned typical arrangement of the thread-loops at right angles 
to the long axis of the nucleus, with a “ polar field” at the 
pole (Polseite), and with an “ antipole”’ (gegen-Polseite) at the 
opposite side, and believes that the threads in the greater 
number of cases lie at the surface of the nucleus (figs. 2 and 8). 
Rabl does not find polar rays in the protoplasm of the cell 
(the “cytaster”’) at this stage (see fig. 7), whereas Flemming 
has observed them in an egg-cell clearly defined in this stage, 
and moreover regards a “ dicentric arrangement ” of the proto- 
plasm as a very early phenomenon in tissue-cells about to divide, 
nothwithstanding that a distinct radial arrangement of the 
protoplasm at two opposite poles is not yet recognisable (see 
later, under van Beneden’s views). 
The primary nuclear figure, which we have now described, 
is termed the ‘denser skein” (dichter Knaiiel) ; it passes 
into the ‘loose skein” (fig. 5). This is brought about 
by the threads becoming thicker and shorter, and uot being 
so tightly coiled. At the same time the single thread 
undergoes transverse division, so that the number of sepa- 
rate loops is increased. abl concludes, from Flemming’s 
numbers and his own, that in one and the same species 
of animal and kind of cell the number of thread-loops 
at this stage is constant. For instance, in the epidermic 
cells of the Salamander there are twenty-four loops. Stras- 
burger and Heuser (97) also give a definite number for certain 
