322 
Di L. SOÓS 
is that synapsis, in which the conjugation is said to take place, is not 
an exclusive property of the germ-cells, since, according to the re¬ 
searches of Marcus (63), it occurs also in the cells of the thymus, i. e., 
synapsis is only a consequence of a certain condition in cell function. 
Applying what we have mentioned above to H. arbustorum , 
I am of the opinion that the parallel arrangement of the threads of 
the leptotene nucleus does not mean the introduction to a parallel 
conjugation, but that the threads have arisen from the splitting of the 
originally united threads. Though the split disappears temporarily and 
reappears only later, yet this phenomenon, as I believe, cannot be 
connected with the conjugation until it be shown that the thread of 
the leptotene nucleus consists of as many parts as the normal number 
of the chromosomes, but it is even doubtful, whether the thread is 
indivisible, or consists of several parts, since the thread of the spireme 
is convoluted so much that its analysis is almost impossible. From the 
recent authors only Schleip has found that it consists of several parts, 
but the majority of observations has given the result that the thread 
divides into parts only in the pachytene stage. We can regard as de¬ 
termined with certainty that the number of the threads of the pachy¬ 
tene nucleus is equal to the reduced number of the chromosomes. 
As regards the question of the reduction this is the most impor¬ 
tant fact. 
The explanation of reduction depends upon the correct interpre¬ 
tation of thi& fact. The next question is whether the origin of as many 
threads as the reduced number of the chromosomes is of equal signi¬ 
ficance with the reduction, or whether that fact must be explained 
otherwise? The partisans of the hypothesis of the parallel conjugation 
are of the opinion that it is only a pseudoreduction, the thread is biva¬ 
lent, and the true reduction takes place later, during the maturation 
divisions, when the chromosomes, united during synapsis, separate from 
one another. Since, however, the hypothesis of parallel conjugation 
cannot be regarded as correct, the conclusions deduced from it must 
he erroneous, therefore the answer to the above mentioned question 
must be that the formation of the segments of the pachytene nucleus 
is of equal significance with the reduction, and that in spermatogene¬ 
sis of H. arbustorum reduction division in Weismann’s sense does not 
occur. Both maturation divisions are equational in Weismann’s sense, 
which take place, as mentioned above in quite the same manner. The 
divisions differ from those of the somatic cells only in the respect 
that the second division very quickly follows the first. The purpose of 
the quick divisions is to reduce the mass of the chromatin. 
