473 
Mother-cells of Smilacina racemosa (LI), Desf. 
seem to be drawn in towards the chromatin granules as nuclear activity 
proceeds would also indicate that the network arrangement is not merely 
a fanciful one. There is nothing to indicate that there is a certain fixed 
number of threads in the resting stage, corresponding to the diploid number 
of chromosomes as stated by Lawson (’ll A and T 2 ). Very few free ends 
were seen in nuclei showing this stage, and it would be impossible to count 
such individual threads if they were present as such in this stage (Figs, i 
and 2). The number of chromatin granules greatly exceeds the number of 
chromosomes in any stage of the division ; so there is nothing in Smilacina 
racemosa to indicate that each chromatin mass is a prochromosome, as is 
claimed by several authors and as emphasized by Stout (T2) for Carex 
aquatilis. If the chromosomes do retain their identity throughout the 
resting stage, this identity is, at least, not recognizable at this stage. 
Lawson (’ll A and T 2 ) and McAllister (T 3 ) show portions of the 
chromatin thread pairing during these early stages. Figs. 1, 2, 3, 4, and 5, 
PI. XXII, of my preparations show similar stages to those figured by Lawson 
and McAllister, but in such nuclei, where there are so many crossings of the 
threads, or where the nuclear contents are in such a finely divided condition, 
it does not seem to be of any special significance that one portion of the 
thread should run along parallel to another portion for a short distance. It 
does not necessarily follow that there is any special relation existing between 
them. The irregularly shaped chromatin granules fuse later and finally 
form a smooth-edged thread. The fact that a few of the granules may fuse 
side by side does not necessarily establish the conclusion that there is 
a general side-by-side pairing throughout the whole nucleus, and, if such 
a phenomenon were characteristic of this stage, it would appear more often 
and in greater regularity. From the conditions as seen during this investi¬ 
gation, it is not possible to agree with Lawson (’ll a) that ‘the chromatin 
threads are undoubtedly double from the beginning’, nor that a definite 
pairing of threads takes place at this stage, nor that ‘ the developing spireme 
was not composed of a single continuous thread, but of a number of double 
threads, and the number corresponds with the diploid number of chromo¬ 
somes . . . which become differentiated later’. McAllister maintains that 
there is no chromatin aggregation into prochromosomes. 
As to the units which go together to make up the chromatin thread, it 
is hard to identify them. We cannot recognize the different hereditary 
characters which develop in the mature individual, in the nuclei of the spore 
mother-cells, and we cannot say with much degree of certainty that it is 
thus or so. A mature individual has too many characteristics for each of 
them to be bound up in a separate chromosome, and this is one argument 
(Farmer ’ 07 ) given for the chromomere as the unit. The colloidal nature of 
the chromatin thread makes it hard to differentiate portions of the thread 
into units, when they are shifting or changing appearance as much as the 
1 i 2 
